Author: "Janine Provost" - Searchworks@Jio Institute Digital Library Search Results

Your search keyword '"Janine Provost"' showing total 57 results

Start Over Author "Janine Provost"

57 results on '"Janine Provost"'

1. Standard solar models with CESAM code

Author: Yveline Lebreton, Gabrielle Berthomieu, Pierre Morel, and Janine Provost
Subjects: Physics, Computer simulation, Opacity, Solar neutrino, Code (cryptography), Astrophysics::Solar and Stellar Astrophysics, Astrophysics::Earth and Planetary Astrophysics, Helioseismology, Astrophysics, Neutrino, Solar physics, Stellar evolution, Astrophysics::Galaxy Astrophysics
Abstract: A new code for stellar evolution, named CESAM, has been constructed at Nice by P. Morel. Standard solar models have been computed using this code. Their global characteristics, predicted capture rates of neutrinos for the chlorine and gallium experiments and their seismological properties are given and compared to the observational constraints. The emphasis is put on the effect of the recent opacities of Livermore for different mixtures, corresponding to recent abundances determination, on the neutrino predictions and the solar oscillations.
Published: 2018

2. Asymptotic g modes: Evidence for a rapid rotation of the solar core

Author: Alan H. Gabriel, François-Xavier Schmider, E. Fossat, Roger K. Ulrich, David Salabert, Sylvaine Turck-Chièze, T. Roca-Cortés, Thierry Corbard, Patrick Boumier, J. M. Robillot, Janine Provost, M. Lazrek, Catherine Renaud, G. Grec, Joseph Louis LAGRANGE (LAGRANGE), Université Côte d'Azur (UCA)-Université Nice Sophia Antipolis (... - 2019) (UNS), COMUE Université Côte d'Azur (2015-2019) (COMUE UCA)-COMUE Université Côte d'Azur (2015-2019) (COMUE UCA)-Observatoire de la Côte d'Azur, Université Côte d'Azur (UCA)-COMUE Université Côte d'Azur (2015-2019) (COMUE UCA)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS), Institut d'astrophysique spatiale (IAS), Université Paris-Sud - Paris 11 (UP11)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS), Département d'Astrophysique, de physique des Particules, de physique Nucléaire et de l'Instrumentation Associée (DAPNIA), Commissariat à l'énergie atomique et aux énergies alternatives (CEA), Université Cadi Ayyad [Marrakech] (UCA), Université Nice Sophia Antipolis (1965 - 2019) (UNS), COMUE Université Côte d'Azur (2015-2019) (COMUE UCA)-COMUE Université Côte d'Azur (2015-2019) (COMUE UCA)-Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire de la Côte d'Azur, COMUE Université Côte d'Azur (2015-2019) (COMUE UCA)-Université Côte d'Azur (UCA)-Université Côte d'Azur (UCA)-Centre National de la Recherche Scientifique (CNRS), and Université Paris-Sud - Paris 11 (UP11)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS)-Centre National d’Études Spatiales [Paris] (CNES)
Subjects: astro-ph.SR, 010504 meteorology & atmospheric sciences, FOS: Physical sciences, Context (language use), Astrophysics, rotation [Sun], Astronomy & Astrophysics, Rotation, 01 natural sciences, Solar core, 0103 physical sciences, Radiative transfer, Astrophysics::Solar and Stellar Astrophysics, Helioseismology, helioseismology [Sun], Sun: oscillations, Very low frequency, 010303 astronomy & astrophysics, Solar and Stellar Astrophysics (astro-ph.SR), Sun: rotation, Sun: helioseismology, 0105 earth and related environmental sciences, Physics, oscillations [Sun], interior [Sun], Spherical harmonics, Astronomy and Astrophysics, Computational physics, Astrophysics - Solar and Stellar Astrophysics, 13. Climate action, Space and Planetary Science, Solar rotation, Sun: interior, [PHYS.ASTR]Physics [physics]/Astrophysics [astro-ph], Astronomical and Space Sciences
Abstract: We present the identification of very low frequency g modes in the asymptotic regime and two important parameters that have long been waited for: the core rotation rate, and the asymptotic equidistant period spacing of these g modes. The GOLF instrument on board the SOHO space observatory has provided two decades of full-disk helioseismic data. In the present study, we search for possible collective frequency modulations that are produced by periodic changes in the deep solar structure. Such modulations provide access to only very low frequency g modes, thus allowing statistical methods to take advantage of their asymptotic properties. For oscillatory periods in the range between 9 and nearly 48 hours, almost 100 g modes of spherical harmonic degree 1 and more than 100 g modes of degree 2 are predicted. They are not observed individually, but when combined, they unambiguouslyprovide their asymptotic period equidistance and rotational splittings, in excellent agreement with the requirements of the asymptotic approximations. Previously, p-mode helioseismology allowed the g-mode period equidistance parameter $P_0$ to be bracketed inside a narrow range, between approximately 34 and 35 minutes. Here, $P_0$ is measured to be 34 min 01 s, with a 1 s uncertainty. The previously unknown g-mode splittings have now been measured from a non-synodic reference with very high accuracy, and they imply a mean weighted rotation of 1277 $\pm$ 10 nHz (9-day period) of their kernels, resulting in a rapid rotation frequency of 1644 $\pm$ 23 nHz (period of one week) of the solar core itself, which is a factor 3.8 $\pm$ 0.1 faster than the rotation of the radiative envelope. The g modes are known to be the keys to a better understanding of the structure and dynamics of the solar core. Their detection with these precise parameters will certainly stimulate a new era of research in this field., 17 pages, 35 figures
Published: 2017

3. Evolution of lithium abundance in the Sun and solar twins

Author: A. V. Oreshina, Janine Provost, Pierre Morel, Frédéric Thévenin, A. B. Gorshkov, V. A. Baturin, Sternberg Astronomical Institute [Moscow], Lomonosov Moscow State University (MSU), Etablissement français du sang [Bourgogne-Franche-Comté] (EFS [Bourgogne-Franche-Comté]), Joseph Louis LAGRANGE (LAGRANGE), Université Côte d'Azur (UCA)-Université Nice Sophia Antipolis (... - 2019) (UNS), COMUE Université Côte d'Azur (2015-2019) (COMUE UCA)-COMUE Université Côte d'Azur (2015-2019) (COMUE UCA)-Observatoire de la Côte d'Azur, and Université Côte d'Azur (UCA)-COMUE Université Côte d'Azur (2015-2019) (COMUE UCA)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS)
Subjects: Solar System, Abundance (chemistry), FOS: Physical sciences, chemistry.chemical_element, Solar radius, Astrophysics, 01 natural sciences, 0103 physical sciences, Lithium burning, Radiative transfer, Sun: abundances, 010303 astronomy & astrophysics, Solar and Stellar Astrophysics (astro-ph.SR), Physics, 010308 nuclear & particles physics, Astronomy and Astrophysics, Scale height, stars: solar-type, Sun: evolution, chemistry, Convection zone, Astrophysics - Solar and Stellar Astrophysics, 13. Climate action, Space and Planetary Science, Lithium, Sun: interior, [PHYS.ASTR]Physics [physics]/Astrophysics [astro-ph]
Abstract: Evolution of the 7Li abundance in the convection zone of the Sun during different stages of its life time is considered to explain its low photospheric value in comparison with that of the solar system meteorites. Lithium is intensively and transiently burned in the early stages of evolution (pre-main sequence, pMS) when the radiative core arises, and then the Li abundance only slowly decreases during the main sequence (MS). We study the rates of lithium burning during these two stages. In a model of the Sun, computed ignoring pMS and without extra-convective mixing (overshooting) at the base of the convection zone, the lithium abundance does not decrease significantly during the MS life time of 4.6 Gyr. Analysis of helioseismic inversions together with post-model computations of chemical composition indicates the presence of the overshooting region and restricts its thickness. It is estimated to be approximately half of the local pressure scale height (0.5HP) which corresponds to 3.8% of the solar radius. Introducing this extra region does not noticeably deplete lithium during the MS stage. In contrast, at the pMS stage, an overshooting region with a value of approximately 0.18HP is enough to produce the observed lithium depletion. If we conclude that the dominant lithium burning takes place during the pMS stage, the dispersion of the lithium abundance in solar twins is explained by different physical conditions, primarily during the early stage of evolution before the MS.
Published: 2017

4. Inter-comparison of the g-, f- and p-modes calculated using different oscillation codes for a given stellar model

Author: Yveline Lebreton, Ian W. Roxburgh, Josefina Montalbán, Joergen Christensen-Dalsgaard, Juan Carlos Suárez, Stéphane Charpinet, A. Moya, Mário J. P. F. G. Monteiro, Richard Scuflaire, Andrea Miglio, M. D. Suran, Janine Provost, Institut Cavanilles de Biodiversitat i Biologia Evolutiva (ICBiBE), Universitat de València (UV), Observatoire de Haute-Provence (OHP), Institut Pythéas (OSU PYTHEAS), Institut de Recherche pour le Développement (IRD)-Aix Marseille Université (AMU)-Institut national de recherche en sciences et technologies pour l'environnement et l'agriculture (IRSTEA)-Centre National de la Recherche Scientifique (CNRS)-Institut de Recherche pour le Développement (IRD)-Aix Marseille Université (AMU)-Institut national de recherche en sciences et technologies pour l'environnement et l'agriculture (IRSTEA)-Centre National de la Recherche Scientifique (CNRS), Laboratoire Astrophysique de Toulouse-Tarbes (LATT), Université Toulouse III - Paul Sabatier (UT3), Université de Toulouse (UT)-Université de Toulouse (UT)-Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire Midi-Pyrénées (OMP), Institut de Recherche pour le Développement (IRD)-Université Toulouse III - Paul Sabatier (UT3), Université de Toulouse (UT)-Université de Toulouse (UT)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National d'Études Spatiales [Toulouse] (CNES)-Centre National de la Recherche Scientifique (CNRS)-Météo-France -Institut de Recherche pour le Développement (IRD)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National d'Études Spatiales [Toulouse] (CNES)-Centre National de la Recherche Scientifique (CNRS)-Météo-France -Centre National de la Recherche Scientifique (CNRS), Galaxies, Etoiles, Physique, Instrumentation (GEPI), Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire de Paris, Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Université Paris Diderot - Paris 7 (UPD7)-Centre National de la Recherche Scientifique (CNRS), Institut d'Astrophysique et de Géophysique [Liège], Université de Liège, Ecole Nationale Supérieure des Télécommunications (ENST), Institut Non Linéaire de Nice Sophia-Antipolis (INLN), Université Nice Sophia Antipolis (1965 - 2019) (UNS), COMUE Université Côte d'Azur (2015-2019) (COMUE UCA)-COMUE Université Côte d'Azur (2015-2019) (COMUE UCA)-Centre National de la Recherche Scientifique (CNRS), Laboratoire de Cosmologie, Astrophysique Stellaire & Solaire, de Planétologie et de Mécanique des Fluides (CASSIOPEE), COMUE Université Côte d'Azur (2015-2019) (COMUE UCA)-COMUE Université Côte d'Azur (2015-2019) (COMUE UCA)-Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire de la Côte d'Azur, COMUE Université Côte d'Azur (2015-2019) (COMUE UCA)-Université Côte d'Azur (UCA)-Université Côte d'Azur (UCA)-Centre National de la Recherche Scientifique (CNRS), Instituto de Astrofísica de Andalucía (IAA), Consejo Superior de Investigaciones Científicas [Madrid] (CSIC), Aix Marseille Université (AMU)-Centre National de la Recherche Scientifique (CNRS)-Institut national de recherche en sciences et technologies pour l'environnement et l'agriculture (IRSTEA)-Institut de Recherche pour le Développement (IRD)-Aix Marseille Université (AMU)-Centre National de la Recherche Scientifique (CNRS)-Institut national de recherche en sciences et technologies pour l'environnement et l'agriculture (IRSTEA)-Institut de Recherche pour le Développement (IRD), Centre National de la Recherche Scientifique (CNRS)-Observatoire Midi-Pyrénées (OMP), Météo France-Centre National d'Études Spatiales [Toulouse] (CNES)-Université Fédérale Toulouse Midi-Pyrénées-Centre National de la Recherche Scientifique (CNRS)-Institut de Recherche pour le Développement (IRD)-Météo France-Centre National d'Études Spatiales [Toulouse] (CNES)-Université Fédérale Toulouse Midi-Pyrénées-Centre National de la Recherche Scientifique (CNRS)-Institut de Recherche pour le Développement (IRD)-Institut national des sciences de l'Univers (INSU - CNRS)-Université Toulouse III - Paul Sabatier (UT3), Université Fédérale Toulouse Midi-Pyrénées, Ecole nationale des télécommunications d'Evry (ENST), Université Nice Sophia Antipolis (... - 2019) (UNS), Université Côte d'Azur (UCA)-COMUE Université Côte d'Azur (2015-2019) (COMUE UCA)-Université Côte d'Azur (UCA)-Centre National de la Recherche Scientifique (CNRS), Université Fédérale Toulouse Midi-Pyrénées-Université Fédérale Toulouse Midi-Pyrénées-Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire Midi-Pyrénées (OMP), Université Fédérale Toulouse Midi-Pyrénées-Centre National de la Recherche Scientifique (CNRS), PSL Research University (PSL)-PSL Research University (PSL)-Centre National de la Recherche Scientifique (CNRS), ENST, Université Côte d'Azur (UCA)-Université Côte d'Azur (UCA)-Centre National de la Recherche Scientifique (CNRS), Université Côte d'Azur (UCA)-Université Côte d'Azur (UCA)-Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire de la Côte d'Azur, Université Côte d'Azur (UCA)-Centre National de la Recherche Scientifique (CNRS), Escuela Politecnica Nacional, Facultad de Geologia, Centro de Investigación Geológica- Guayaquil (CIGG), and Petroproducción
Subjects: Physics, 010504 meteorology & atmospheric sciences, Field (physics), Oscillation, Astrophysics (astro-ph), FOS: Physical sciences, Astronomy and Astrophysics, Richardson extrapolation, Astrophysics, 01 natural sciences, Numerical integration, [PHYS.ASTR.CO]Physics [physics]/Astrophysics [astro-ph]/Cosmology and Extra-Galactic Astrophysics [astro-ph.CO], Gravitational constant, Distribution (mathematics), Space and Planetary Science, 0103 physical sciences, Range (statistics), Sensitivity (control systems), Statistical physics, 010303 astronomy & astrophysics, 0105 earth and related environmental sciences
Abstract: In order to make astroseismology a powerful tool to explore stellar interiors, different numerical codes should give the same oscillation frequencies for the same input physics. This work is devoted to test, compare and, if needed, optimize the seismic codes used to calculate the eigenfrequencies to be finally compared with observations. The oscillation codes of nine research groups in the field have been used in this study. The same physics has been imposed for all the codes in order to isolate the non-physical dependence of any possible difference. Two equilibrium models with different grids, 2172 and 4042 mesh points, have been used, and the latter model includes an explicit modelling of semiconvection just outside the convective core. Comparing the results for these two models illustrates the effect of the number of mesh points and their distribution in particularly critical parts of the model, such as the steep composition gradient outside the convective core. A comprehensive study of the frequency differences found for the different codes is given as well. These differences are mainly due to the use of different numerical integration schemes. The use of a second-order integration scheme plus a Richardson extrapolation provides similar results to a fourth-order integration scheme. The proper numerical description of the Brunt-Vaisala frequency in the equilibrium model is also critical for some modes. An unexpected result of this study is the high sensitivity of the frequency differences to the inconsistent use of values of the gravitational constant (G) in the oscillation codes, within the range of the experimentally determined ones, which differ from the value used to compute the equilibrium model., Comment: 18 pages, 34 figures
Published: 2008

5. Asteroseismology and evolutionary status of Procyon A

Author: M. Martic, Janine Provost, Gabrielle Berthomieu, Pierre Morel, Laboratoire de Cosmologie, Astrophysique Stellaire & Solaire, de Planétologie et de Mécanique des Fluides (CASSIOPEE), Université Nice Sophia Antipolis (... - 2019) (UNS), COMUE Université Côte d'Azur (2015-2019) (COMUE UCA)-COMUE Université Côte d'Azur (2015-2019) (COMUE UCA)-Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire de la Côte d'Azur, Université Côte d'Azur (UCA)-COMUE Université Côte d'Azur (2015-2019) (COMUE UCA)-Université Côte d'Azur (UCA)-Centre National de la Recherche Scientifique (CNRS), Service d'aéronomie (SA), Université de Versailles Saint-Quentin-en-Yvelines (UVSQ)-Université Pierre et Marie Curie - Paris 6 (UPMC)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS), Université Nice Sophia Antipolis (1965 - 2019) (UNS), and COMUE Université Côte d'Azur (2015-2019) (COMUE UCA)-Université Côte d'Azur (UCA)-Université Côte d'Azur (UCA)-Centre National de la Recherche Scientifique (CNRS)
Subjects: stars, Physics, [SDU.ASTR]Sciences of the Universe [physics]/Astrophysics [astro-ph], 010308 nuclear & particles physics, Metallicity, Procyon A, Spectral density, Astronomy and Astrophysics, Astrophysics, Effective temperature, 01 natural sciences, Asteroseismology, Stars, Space and Planetary Science, oscillations, evolution, 0103 physical sciences, Astrophysics::Solar and Stellar Astrophysics, 010303 astronomy & astrophysics, Stellar evolution
Abstract: Models of Procyon A satisfying the actual observational constraints, particularly the asteroseismic ones, are discussed. The oscillations of these models were computed and analysed. We looked for seismic signatures of the evolutionary status of Procyon A. We show that the behavior of the small frequency spacings, particularly allows us to distinguish between main sequence and post-main sequence models, all satisfying the observational constraints on mass, effective temperature, radius, and surface metallicity of Procyon A. We also introduce a new seismic evolution criterion, , based on the comparison of the low and high frequency parts of the power spectrum. The comparison of the seismic properties of the models with the available asteroseismic observations does not allow us to definitely decide on the stage of evolution of Procyon A. Much more accurate frequencies must be obtained especially in the low-frequency domain to distinguish between the models.
Published: 2006

6. Effect of microscopic diffusion on asteroseismic properties of intermediate-mass stars

Author: Lionel Bigot, Pierre Morel, Gabrielle Berthomieu, Janine Provost, Laboratoire de Cosmologie, Astrophysique Stellaire & Solaire, de Planétologie et de Mécanique des Fluides (CASSIOPEE), Université Nice Sophia Antipolis (... - 2019) (UNS), COMUE Université Côte d'Azur (2015-2019) (COMUE UCA)-COMUE Université Côte d'Azur (2015-2019) (COMUE UCA)-Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire de la Côte d'Azur, and Université Côte d'Azur (UCA)-COMUE Université Côte d'Azur (2015-2019) (COMUE UCA)-Université Côte d'Azur (UCA)-Centre National de la Recherche Scientifique (CNRS)
Subjects: stars, 010504 meteorology & atmospheric sciences, Stellar mass, Metallicity, oscillations -stars, Astrophysics::Cosmology and Extragalactic Astrophysics, Astrophysics, 01 natural sciences, Luminosity, evolution -stars, 0103 physical sciences, Astrophysics::Solar and Stellar Astrophysics, Diffusion (business), 010303 astronomy & astrophysics, Astrophysics::Galaxy Astrophysics, oscillation -diffusion, 0105 earth and related environmental sciences, Physics, Astrophysics::Instrumentation and Methods for Astrophysics, Astronomy and Astrophysics, Astrometry, Effective temperature, Photometry (astronomy), Stars, [SDU]Sciences of the Universe [physics], Space and Planetary Science, Astrophysics::Earth and Planetary Astrophysics
Abstract: Astronomy and Astrophysics, 432, pp. 225-233, http://dx.doi.org./10.1051/0004-6361:20041387; International audience; Results on the effects of microscopic diffusion on the modeling and oscillations of solar-like stars are discussed. Comparisons between models with and without microscopic diffusion, subjected to observational constraints, namely effective temperature, luminosity, surface metallicity and mass derived from photometry, spectroscopy and astrometry, are presented. We point out and discuss a signature of microscopic diffusion on the oscillation frequencies.
Published: 2005

7. VINCI/VLTI Observations of Main Sequence Stars

Author: Emmanuel di Folco, Frédéric Thévenin, Damien Ségransan, Janine Provost, Pierre Kervella, Pierre Morel, Pascal Bordé, Thierry Forveille, Didier Queloz, Gabrielle Berthomieu, Laboratoire d'études spatiales et d'instrumentation en astrophysique (LESIA), Université Pierre et Marie Curie - Paris 6 (UPMC)-Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire de Paris, Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Université Paris Diderot - Paris 7 (UPD7)-Centre National de la Recherche Scientifique (CNRS), Pôle Astronomie du LESIA, and Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Université Paris Diderot - Paris 7 (UPD7)-Centre National de la Recherche Scientifique (CNRS)-Université Pierre et Marie Curie - Paris 6 (UPMC)-Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire de Paris
Subjects: Physics, Photometry (optics), Stars, Planet, Brown dwarf, Astrophysics::Solar and Stellar Astrophysics, Astronomy, Astrophysics::Earth and Planetary Astrophysics, [PHYS.ASTR]Physics [physics]/Astrophysics [astro-ph], Stellar classification, Astrophysics::Galaxy Astrophysics, Exoplanet, Main sequence
Abstract: Main Sequence (MS) stars are by far the most numerous class in the Universe. They are often somewhat neglected as they are relatively quiet objects (but exceptions exist), though they bear testimony of the past and future of our Sun. An important characteristic of the MS stars, particularly the solar-type ones, is that they host the large majority of the known extrasolar planets. Moreover, at the bottom of the MS, the red M dwarfs pave the way to understanding the physics of brown dwarfs and giant planets. We have measured very precise angular diameters from recent VINCI/VLTI interferometric observations of a number of MS stars in the K band, with spectral types between A1V and M5.5V. They already cover a wide range of effective temperatures and radii. Combined with precise Hipparcos parallaxes, photometry, spectroscopy as well as the asteroseismic information available for some of these stars, the angular diameters put strong constraints on the detailed models of these stars, and therefore on the physical processes at play.
Published: 2004

8. The diameter and evolutionary state of Procyon A

Author: Pascal Bordé, Janine Provost, Gabrielle Berthomieu, Pierre Kervella, Pierre Morel, F. Thévenin, European Southern Observatory, Laboratoire d'études spatiales et d'instrumentation en astrophysique (LESIA), Université Pierre et Marie Curie - Paris 6 (UPMC)-Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire de Paris, Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Université Paris Diderot - Paris 7 (UPD7)-Centre National de la Recherche Scientifique (CNRS), Pôle Astronomie du LESIA, Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Université Paris Diderot - Paris 7 (UPD7)-Centre National de la Recherche Scientifique (CNRS)-Université Pierre et Marie Curie - Paris 6 (UPMC)-Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire de Paris, Observatoire de la Côte d'Azur, and COMUE Université Côte d'Azur (2015-2019) (COMUE UCA)-Université Côte d'Azur (UCA)
Subjects: Physics, Oscillation, chemistry.chemical_element, Astronomy and Astrophysics, Astrophysics::Cosmology and Extragalactic Astrophysics, Astrophysics, Mass ratio, Luminosity, chemistry, Space and Planetary Science, Angular diameter, Frequency separation, Astrophysics::Solar and Stellar Astrophysics, Astrophysics::Earth and Planetary Astrophysics, [PHYS.ASTR]Physics [physics]/Astrophysics [astro-ph], Parallax, Mass fraction, Astrophysics::Galaxy Astrophysics, Helium
Abstract: International audience; We report the angular diameter measurement obtained with the VINCI/VLTI instrument on the nearby star Procyon A (alpha CMi A, F5IV-V), at a relative precision of ± 0.9%. We obtain a uniform disk angular diameter in the K band of thetaUD = 5.376±0.047 mas and a limb darkened value of thetaLD = 5.448±0.053 mas. Together with the HIPPARCOS parallax, this gives a linear diameter of 2.048±0.025 D&sun;. We use this result in combination with spectroscopic, photometric and asteroseismic constraints to model this star with the CESAM code. One set of modeling parameters that reproduces the observations within their error bars are an age of 2314 Myr, an initial helium mass fraction Y_i=0.301 and an initial mass ratio of heavy elements to hydrogen (Z/X)i=0.0314. We also computed the adiabatic oscillation spectrum of our model of Procyon A, giving a mean large frequency separation of /line{Deltanu0}≈ 54.7 muHz. This value is in agreement with the seismic observations by Martic et al. (\cite{martic}, \cite{martic01}). The interferometric diameter and the asteroseismic large frequency spacing together suggest a mass closer to 1.4 M&sun; than to 1.5 M&sun;. We conclude that Procyon is currently ending its life on the main sequence, as its luminosity class indicates.
Published: 2003

9. Asteroseismology and calibration ofα Cen binary system

Author: Janine Provost, François Bouchy, Fabien Carrier, Pierre Morel, Gabrielle Berthomieu, and Frédéric Thévenin
Subjects: Physics, Metallicity, chemistry.chemical_element, Astronomy and Astrophysics, Astrophysics, Alpha (navigation), Asteroseismology, chemistry, Space and Planetary Science, Calibration, Binary system, Mass fraction, Helium, Visual binary
Abstract: Using the oscillation frequencies of alpha Cen A recently discovered by Bouchy & Carrier, the available astrometric, photometric and spectroscopic data, we tried to improve the calibration of the visual binary system alpha Cen. With the revisited masses of Pourbaix et al. (2002) we do not succeed to obtain a solution satisfying all the seismic observational constraints. Relaxing the constraints on the masses, we have found an age t_alpha Cen=4850+-500 Myr, an initial helium mass fraction Y_i = 0.300+-0.008, and an initial metallicity (Z/X)_i=0.0459+-0.0019, with M_A=1.100+-0.006M_o and M_B=0.907+-0.006M_o for alpha Cen A&B.
Published: 2002

10. A search for solar $\vec{g}$ modes in the GOLF data

Author: A. H. Gabriel, Luca Bertello, Pere L. Palle, C. Renaud, J. M. Robillot, Douglas Gough, Rafael A. García, T. Appourchaux, T. Roca Cortés, Janine Provost, Sylvaine Turck-Chièze, Roger K. Ulrich, J. Charra, Frédéric Baudin, Gabrielle Berthomieu, Patrick Boumier, and S. Thiery
Subjects: Physics, Series (mathematics), Mode (statistics), Astronomy and Astrophysics, Astrophysics, Solar physics, Theoretical physics, Amplitude, Space and Planetary Science, Helioseismology, Limit (mathematics), Statistical physics, Multiplet, Noise (radio)
Abstract: With over 5 years of GOLF data having some 90% continuity, a new attempt has been made to search for possible solarg modes. Statistical methods are used, based on the minimum of assumptions regarding the solar physics; namely that mode line-widths are small compared with the inverse of the observing time, and that modes are sought in the frequency interval 150 to 400Hz. A number of simulations are carried out in order to understand the expected behaviour of a system consisting principally of a solar noise continuum overlaid with some weak sharp resonances. The method adopted is based on the FFT analysis of a time series with zero-padding by a factor of 5. One prominent resonance at 284.666Hz coincides with a previous tentative assignment as one member of an n = 1, l = 1, p-mode multiplet. Components of two multiplets, previously tentatively identified as possibleg-mode candidates from the GOLF data in 1998, continue to be found, although their statistical significance is shown to be insucient, within the present assumption regarding the nature of the signal. An upper limit to the amplitude of anyg mode present is calculated using two dierent statistical approaches, according to either the assumed absence (H0 hypothesis) or the assumed presence (H1 hypothesis) of a signal. The former yields a slightly lower limit of around 6 mm/s.
Published: 2002

11. TheζHerculis binary system revisited

Author: Pierre Morel, Frédéric Thévenin, Janine Provost, and Gabrielle Berthomieu
Subjects: Physics, Oscillation, Astrophysics (astro-ph), FOS: Physical sciences, Binary number, Astronomy and Astrophysics, Astrophysics, Mass ratio, Superposition principle, Space and Planetary Science, Astrophysics::Solar and Stellar Astrophysics, Astrophysics::Earth and Planetary Astrophysics, Binary system, Adiabatic process, Envelope (waves), Visual binary
Abstract: We have revisited the calibration of the visual binary system Zeta Herculis with the goal to give the seismological properties of the G0 IV sub-giant Zeta Her A. We have used the most recent physical and observational data. For the age we have obtained 3387 Myr, for the masses respectively 1.45 and 0.98 solar mass, for the initial helium mass fraction 0.243, for the initial mass ratio of heavy elements to hydrogen 0.0269 and for the mixing-length parameters respectively 0.92 and 0.90 using the Canuto & Mazitelli (1991, 1992) convection theory. Our results do not exclude that Zeta Her A is itself a binary sub-system; the mass of the hypothetical unseen companion would be smaller than 0.05 solar mass. The adiabatic oscillation spectrum of Zeta Her A is found to be a complicated superposition of acoustic and gravity modes; some of them have a dual character. This greatly complicates the classification of the non-radial modes. The echelle diagram used by the observers to extract the frequencies will work for ell=0, 2, 3. The large difference is found to be of the order of 42 mu Hz, in agreement with the Martic et al. (2001) seismic observations., 12 pages, A&A in press
Published: 2001

12. Solar Neutrino Emission Deduced from a Seismic Model

Author: Jørgen Christensen-Dalsgaard, Ian W. Roxburgh, Sebastien Couvidat, Roger K. Ulrich, Sylvaine Turck-Chièze, Douglas Gough, Gabrielle Berthomieu, A. H. Gabriel, Allan Sacha Brun, Alexander G. Kosovichev, Rafael A. García, T. Roca-Cortes, and Janine Provost
Subjects: Nuclear reaction, Physics, Standard solar model, Turbulence, Solar neutrino, Astronomy and Astrophysics, Astrophysics, law.invention, Luminosity, Space and Planetary Science, law, Observatory, Astrophysics::Solar and Stellar Astrophysics, Hydrostatic equilibrium, Neutrino
Abstract: Three helioseismic instruments on the Solar and Heliospheric Observatory have observed the Sun almost continuously since early 1996. This has led to detailed study of the biases induced by the instruments that measure intensity or Doppler velocity variation. Photospheric turbulence hardly influences the tiny signature of conditions in the energy-generating core in the low-order modes, which are therefore very informative. We use sound-speed and density profiles inferred from GOLF and MDI data including these modes, together with recent improvements to stellar model computations, to build a spherically symmetric seismically adjusted model in agreement with the observations. The model is in hydrostatic and thermal balance and produces the present observed luminosity. In constructing the model, we adopt the best physics available, although we adjust some fundamental ingredients, well within the commonly estimated errors, such as the p-p reaction rate (+1%) and the heavy-element abundance (+3.5%); we also examine the sensitivity of the density profile to the nuclear reaction rates. Then, we deduce the corresponding emitted neutrino fluxes and consequently demonstrate that it is unlikely that the deficit of the neutrino fluxes measured on Earth can be explained by a spherically symmetric classical model without neutrino flavor transitions. Finally, we discuss the limitations of our results and future developments.
Published: 2001

13. Observational Upper Limits to Low‐Degree Solarg‐Modes

Author: Claus Fröhlich, William J. Chaplin, B. N. Andersen, Janine Provost, Douglas Gough, Wolfgang Finsterle, T. Toutain, Philip H. Scherrer, G. R. Isaak, Yvonne Elsworth, Alexander G. Kosovichev, Gabrielle Berthomieu, J. T. Hoeksema, T. Appourchaux, and Takashi Sekii
Subjects: Physics, Solar constant, business.industry, Astronomy and Astrophysics, Astrophysics, Solar irradiance, Birmingham Solar Oscillations Network, symbols.namesake, Amplitude, Optics, Space and Planetary Science, symbols, Coronal mass ejection, Astrophysics::Solar and Stellar Astrophysics, Helioseismology, business, Doppler effect, Noise (radio)
Abstract: Observations made by the Michelson Doppler Imager (MDI) and Variability of solar IRradiance and Gravity Oscillations (VIRGO) on the Solar and Heliospheric Observatory (SOHO) and by the ground-based Birmingham Solar Oscillations Network (BiSON) and Global Oscillations Network Group (GONG) have been used in a concerted effort to search for solar gravity oscillations. All spectra are dominated by solar noise in the frequency region from 100 to 1000 μHz, where g-modes are expected to be found. Several methods have been used in an effort to extract any g-mode signal present. These include (1) the correlation of data—both full-disk and imaged (with different spatial-mask properties)—collected over different time intervals from the same instrument, (2) the correlation of near-contemporaneous data from different instruments, and (3) the extraction—through the application of complex filtering techniques—of the coherent part of data collected at different heights in the solar atmosphere. The detection limit is set by the loss of coherence caused by the temporal evolution and the motion (e.g., rotation) of superficial structures. Although we cannot identify any g-mode signature, we have nevertheless set a firm upper limit to the amplitudes of the modes: at 200 μHz, they are below 10 mm s-1 in velocity, and below 0.5 parts per million in intensity. The velocity limit corresponds very approximately to a peak-to-peak vertical displacement of δR/R☉ = 2.3 × 10-8 at the solar surface. These levels which are much lower than prior claims, are consistent with theoretical predictions.
Published: 2000

14. Tracking Solar Gravity Modes: The Dynamics of the Solar Core

Author: Savita Mathur, Rafael A. García, Janine Provost, Sylvaine Turck-Chièze, Pere L. Palle, Antonio Eff-Darwich, J. Ballot, S. J. Jiménez-Reyes, Laboratoire de Cosmologie, Astrophysique Stellaire & Solaire, de Planétologie et de Mécanique des Fluides (CASSIOPEE), Université Nice Sophia Antipolis (... - 2019) (UNS), COMUE Université Côte d'Azur (2015-2019) (COMUE UCA)-COMUE Université Côte d'Azur (2015-2019) (COMUE UCA)-Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire de la Côte d'Azur, and Université Côte d'Azur (UCA)-COMUE Université Côte d'Azur (2015-2019) (COMUE UCA)-Université Côte d'Azur (UCA)-Centre National de la Recherche Scientifique (CNRS)
Subjects: Physics, Gravity (chemistry), Multidisciplinary, 010308 nuclear & particles physics, business.industry, Oscillation, Solar radius, Rotation, 01 natural sciences, Radiation zone, Computational physics, Dipole, Optics, Solar core, 13. Climate action, Physics::Space Physics, 0103 physical sciences, Astrophysics::Solar and Stellar Astrophysics, Astrophysics::Earth and Planetary Astrophysics, Helioseismology, business, 010303 astronomy & astrophysics
Abstract: Solar gravity modes have been actively sought because they directly probe the solar core (below 0.2 solar radius), but they have not been conclusively detected in the Sun because of their small surface amplitudes. Using data from the Global Oscillation at Low Frequency instrument, we detected a periodic structure in agreement with the period separation predicted by the theory for gravity dipole modes. When studied in relation to simulations including the best physics of the Sun determined through the acoustic modes, such a structure favors a faster rotation rate in the core than in the rest of the radiative zone.
Published: 2007

15. First results from VIRGO on SoHO

Author: B. N. Andersen, Christoph Wehrli, Janine Provost, Douglas Gough, V. Domingo, T. Appourchaux, Takashi Sekii, Wolfgang Finsterle, J. Romero, Hansjörg Roth, T. Leifsen, T. Toutain, María Gómez, Gabrielle Berthomieu, Udo Telljohann, J. M. Pap, D. Crommelynck, M. Lombaerts, A. Jiménez, Claus Fröhlich, T. Roca Cortes, and Alain Fichot
Subjects: Background noise, Physics, Sunspot, Amplitude, Observatory, Physics::Space Physics, Modulation (music), Astrophysics::Solar and Stellar Astrophysics, Flux, Astrophysics::Earth and Planetary Astrophysics, Astrophysics, Solar irradiance, Excitation
Abstract: First results from the 4-6 months observations of the VIRGO experiment (Variability of solar IRradiance and Gravity Oscillations) on the ESA/NASA Mission SOHO (Solar and Heliospheric Observatory) are reported. The time series are evaluated in terms of solar irradiance variability, solar background noise characteristics and p-mode oscillations. The solar irradiance is modulated by the passage of active regions across the disk, but not all of the modulation is straightforwardly explained in terms of sunspot flux blocking and facular enhancement. The observed p-mode frequencies are more-or-less in agreement with earlier measurements, but it is interesting to note that systematic differences seem to exist between the observations in different colours. There is also evidence that magnetic activity plays a significant role in the dynamics of the oscillations beyond its modulation of the resonant frequencies. Moreover, by comparing the amplitudes of different components of p-mode multiplets, each of which are influenced differently by spatial inhomogeneity, we have found that activity enhances excitation.
Published: 1997

16. Asymptotic and measured large frequency separations

Author: Eric Michel, Benoit Mosser, Annie Baglin, M. J. Goupil, Claude Catala, Janine Provost, Michel Auvergne, Kevin Belkacem, C. Barban, Reza Samadi, Instituto de Astrofisica de Canarias (IAC), Laboratoire d'études spatiales et d'instrumentation en astrophysique (LESIA), Université Pierre et Marie Curie - Paris 6 (UPMC)-Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire de Paris, Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Université Paris Diderot - Paris 7 (UPD7)-Centre National de la Recherche Scientifique (CNRS), Agro-écologie, Hydrogéochimie, Milieux et Ressources (AGHYLE), UniLaSalle, Laboratoire de Cosmologie, Astrophysique Stellaire & Solaire, de Planétologie et de Mécanique des Fluides (CASSIOPEE), Université Nice Sophia Antipolis (... - 2019) (UNS), COMUE Université Côte d'Azur (2015-2019) (COMUE UCA)-COMUE Université Côte d'Azur (2015-2019) (COMUE UCA)-Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire de la Côte d'Azur, Université Côte d'Azur (UCA)-COMUE Université Côte d'Azur (2015-2019) (COMUE UCA)-Université Côte d'Azur (UCA)-Centre National de la Recherche Scientifique (CNRS), Université Nice Sophia Antipolis (1965 - 2019) (UNS), and COMUE Université Côte d'Azur (2015-2019) (COMUE UCA)-Université Côte d'Azur (UCA)-Université Côte d'Azur (UCA)-Centre National de la Recherche Scientifique (CNRS)
Subjects: Physics, [PHYS]Physics [physics], Stellar mass, 010308 nuclear & particles physics, Oscillation, FOS: Physical sciences, Astronomy and Astrophysics, Astrophysics, Curvature, 01 natural sciences, Asteroseismology, Stars, Astrophysics - Solar and Stellar Astrophysics, Space and Planetary Science, 0103 physical sciences, Astrophysics::Solar and Stellar Astrophysics, Stellar structure, Astrophysics::Earth and Planetary Astrophysics, Asymptotic expansion, [PHYS.ASTR]Physics [physics]/Astrophysics [astro-ph], 010303 astronomy & astrophysics, Stellar density, Astrophysics::Galaxy Astrophysics, Solar and Stellar Astrophysics (astro-ph.SR), ComputingMilieux_MISCELLANEOUS
Abstract: With the space-borne missions CoRoT and Kepler, a large amount of asteroseismic data is now available. So-called global oscillation parameters are inferred to characterize the large sets of stars, to perform ensemble asteroseismology, and to derive scaling relations. The mean large separation is such a key parameter. It is therefore crucial to measure it with the highest accuracy. As the conditions of measurement of the large separation do not coincide with its theoretical definition, we revisit the asymptotic expressions used for analysing the observed oscillation spectra. Then, we examine the consequence of the difference between the observed and asymptotic values of the mean large separation. The analysis is focused on radial modes. We use series of radial-mode frequencies to compare the asymptotic and observational values of the large separation. We propose a simple formulation to correct the observed value of the large separation and then derive its asymptotic counterpart. We prove that, apart from glitches due to stellar structure discontinuities, the asymptotic expansion is valid from main-sequence stars to red giants. Our model shows that the asymptotic offset is close to 1/4, as in the theoretical development. High-quality solar-like oscillation spectra derived from precise photometric measurements are definitely better described with the second-order asymptotic expansion. The second-order term is responsible for the curvature observed in the \'echelle diagrams used for analysing the oscillation spectra and this curvature is responsible for the difference between the observed and asymptotic values of the large separation. Taking it into account yields a revision of the scaling relations providing more accurate asteroseismic estimates of the stellar mass and radius., Comment: accepted in A&A
Published: 2012

17. VIRGO: Experiment for helioseismology and solar irradiance monitoring

Author: Udo Telljohann, B. N. Andersen, Hansjörg Roth, Andrew R. Jones, José Miguel Herreros, V. Domingo, Janine Provost, T. Toutain, Philippe Delache, Claus Fröhlich, Christoph Wehrli, J. M. Pap, D. Crommelynck, André Chevalier, Douglas Gough, Maria F. Gómez, Alain Fichot, Werner Däppen, J. Romero, Richard C. Willson, Antonio Jiménez, Todd Hoeksema, T. Appourchaux, Gabrielle Berthomieu, and Teodoro Roca Cortés
Subjects: Physics, Brightness, Radiometer, Irradiance, Astronomy, Astronomy and Astrophysics, Photometer, Solar physics, Solar irradiance, law.invention, Space and Planetary Science, law, Radiance, Astrophysics::Solar and Stellar Astrophysics, Astrophysics::Earth and Planetary Astrophysics, Helioseismology, Remote sensing
Abstract: The scientific objective of the VIRGO experiment (Variability of solar IRradiance and Gravity Oscillations) is to determine the characteristics of pressure and internal gravity oscillations by observing irradiance and radiance variations, to measure the solar total and spectral irradiance and to quantify their variability over periods of days to the duration of the mission. With these data helioseismological methods can be used to probe the solar interior. Certain characteristics of convection and its interaction with magnetic fields, related to, for example, activity, will be studied from the results of the irradiance monitoring and from the comparison of amplitudes and phases of the oscillations as manifest in brightness from VIRGO, in velocity from GOLF, and in both velocity and continuum intensity from SOI/MDI. The VIRGO experiment contains two different active-cavity radiometers for monitoring the solar ‘constant’, two three-channel sunphotometers (SPM) for the measurement of the spectral irradiance at 402, 500 and 862 nm, and a low-resolution imager (LOI) with 12 pixels, for the measurement of the radiance distribution over the solar disk at 500 um. In this paper the scientific objectives of VIRGO are presented, the instruments and the data acquisition and control system are described in detail, and their measured performance is given.
Published: 1995

18. Low frequency signal in the GOLF measurements

Author: Gérard Grec, Janine Provost, C. Renaud, Laboratoire de Cosmologie, Astrophysique Stellaire & Solaire, de Planétologie et de Mécanique des Fluides (CASSIOPEE), Université Nice Sophia Antipolis (... - 2019) (UNS), COMUE Université Côte d'Azur (2015-2019) (COMUE UCA)-COMUE Université Côte d'Azur (2015-2019) (COMUE UCA)-Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire de la Côte d'Azur, and Université Côte d'Azur (UCA)-COMUE Université Côte d'Azur (2015-2019) (COMUE UCA)-Université Côte d'Azur (UCA)-Centre National de la Recherche Scientifique (CNRS)
Subjects: History, Spectrum analyzer, Spectral flux, 010308 nuclear & particles physics, Spectral density, Low frequency, 01 natural sciences, Signal, Spectral line, Computer Science Applications, Education, Computational physics, [SDU]Sciences of the Universe [physics], Frequency domain, 0103 physical sciences, Electronic engineering, 010303 astronomy & astrophysics, Frequency modulation, ComputingMilieux_MISCELLANEOUS, Mathematics
Abstract: This paper shows the results obtained using a revisited method to normalize the velocity evaluation extracted from the measurements, for roughly 14 years of GOLF data. For the search of g modes, we calculate the low frequency power spectrum of the signal with 2 different approaches: • The classical calculation of the power spectrum of the velocity signal. • An alternative calculation, extracting first the variations along the time of the p-mode frequencies, then calculating the power spectrum of those frequency modulation [4]. Both spectra are compared to the g-mode frequency spectrum calculated for a solar model. Several observed frequencies are in close agreement with the calculated g modes. A careful statistical analysis of this result should now follow.
Published: 2011

19. Open issues in probing interiors of solar-like oscillating main sequence stars: 2. Diversity in the HR diagram

Author: João Pedro Marques, Yveline Lebreton, S. Deheuvels, O. Benomar, M. J. Goupil, Janine Provost, Laboratoire d'études spatiales et d'instrumentation en astrophysique (LESIA), Université Pierre et Marie Curie - Paris 6 (UPMC)-Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire de Paris, Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Université Paris Diderot - Paris 7 (UPD7)-Centre National de la Recherche Scientifique (CNRS), Galaxies, Etoiles, Physique, Instrumentation (GEPI), Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire de Paris, Institut de Physique de Rennes (IPR), Université de Rennes 1 (UR1), Université de Rennes (UNIV-RENNES)-Université de Rennes (UNIV-RENNES)-Centre National de la Recherche Scientifique (CNRS), IFP Energies nouvelles (IFPEN), Alcatel-Thalès III-V lab (III-V Lab), THALES-ALCATEL, Laboratoire de Cosmologie, Astrophysique Stellaire & Solaire, de Planétologie et de Mécanique des Fluides (CASSIOPEE), Université Nice Sophia Antipolis (... - 2019) (UNS), COMUE Université Côte d'Azur (2015-2019) (COMUE UCA)-COMUE Université Côte d'Azur (2015-2019) (COMUE UCA)-Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire de la Côte d'Azur, Université Côte d'Azur (UCA)-COMUE Université Côte d'Azur (2015-2019) (COMUE UCA)-Université Côte d'Azur (UCA)-Centre National de la Recherche Scientifique (CNRS), Université de Rennes (UR)-Centre National de la Recherche Scientifique (CNRS), and THALES [France]-ALCATEL
Subjects: Physics, History, [SDU.ASTR]Sciences of the Universe [physics]/Astrophysics [astro-ph], 010308 nuclear & particles physics, Hertzsprung–Russell diagram, Astronomy, FOS: Physical sciences, 01 natural sciences, Kepler, Computer Science Applications, Education, Stars, symbols.namesake, Astrophysics - Solar and Stellar Astrophysics, [SDU]Sciences of the Universe [physics], 0103 physical sciences, symbols, Astrophysics::Solar and Stellar Astrophysics, Astrophysics::Earth and Planetary Astrophysics, 010303 astronomy & astrophysics, Main sequence, Solar and Stellar Astrophysics (astro-ph.SR), Astrophysics::Galaxy Astrophysics, ComputingMilieux_MISCELLANEOUS
Abstract: We review some major open issues in the current modelling of low and intermediate mass, main sequence stars based on seismological studies. The solar case was discussed in a companion paper, here several issues specific to other stars than the Sun are illustrated with a few stars observed with CoRoT and expectations from Kepler data., GONG 2010 - SoHO 24, A new era of seismology of the Sun and solar-like stars, To be published in the Journal of Physics: Conference Series (JPCS)
Published: 2010

20. A MULTI-SITE CAMPAIGN TO MEASURE SOLAR-LIKE OSCILLATIONS IN PROCYON. II. MODE FREQUENCIES

Author: D. Sosnowska, William J. Chaplin, Hiroyasu Ando, Sylvaine Turck-Chièze, R. P. Butler, T. Appourchaux, Tiago L. Campante, T. H. Dall, J. C. Lebrun, Rafael A. García, Gabrielle Berthomieu, Rosario Cosentino, Saskia Hekker, Silvio Leccia, M. Hartmann, S. Frandsen, B. Mosser, K. Brogaard, Michael Endl, Sabine Reffert, A. P. Hatzes, Jørgen Christensen-Dalsgaard, Christoffer Karoff, Simon J. O'Toole, J. Lundgreen-Nielsen, Janine Provost, Frank Grundahl, E. Michel, László L. Kiss, M. Bazot, H. Bruntt, S. Benatti, Caroline Barban, T. S. Metcalfe, P. Eggenberger, M. Martic, Fabien Carrier, Jean-Loup Bertaux, Robert A. Wittenmyer, B. Sato, Hideyuki Izumiura, Timothy R. Bedding, Eric Stempels, J. H. M. M. Schmitt, Riccardo Claudi, L. Glowienka, Eiji Kambe, Hans Kjeldsen, Torben Arentoft, Alfio Bonanno, Sydney Institute for Astronomy (SIfA), The University of Sydney, Danish AsteroSeismology Centre (DASC), Aarhus University [Aarhus], Centro de Astrofísica da Universidade do Porto (CAUP), Universidade do Porto = University of Porto, Institut d'astrophysique spatiale (IAS), Université Paris-Sud - Paris 11 (UP11)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS)-Centre National d’Études Spatiales [Paris] (CNES), INAF - Osservatorio Astrofisico di Catania (OACT), Istituto Nazionale di Astrofisica (INAF), School of Physics and Astronomy [Birmingham], University of Birmingham [Birmingham], Département d'Astrophysique, de physique des Particules, de physique Nucléaire et de l'Instrumentation Associée (DAPNIA), Commissariat à l'énergie atomique et aux énergies alternatives (CEA), Laboratoire Atmosphères, Milieux, Observations Spatiales (LATMOS), Université de Versailles Saint-Quentin-en-Yvelines (UVSQ)-Université Pierre et Marie Curie - Paris 6 (UPMC)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS), Observatoire de Paris - Site de Paris (OP), Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire de Paris, Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Centre National de la Recherche Scientifique (CNRS), Laboratoire d'études spatiales et d'instrumentation en astrophysique (LESIA), Université Pierre et Marie Curie - Paris 6 (UPMC)-Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire de Paris, Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Université Paris Diderot - Paris 7 (UPD7)-Centre National de la Recherche Scientifique (CNRS), Department of Terrestrial Magnetism [Carnegie Institution], Carnegie Institution for Science, Astrophysique Interprétation Modélisation (AIM (UMR7158 / UMR_E_9005 / UM_112)), Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Institut national des sciences de l'Univers (INSU - CNRS)-Université Paris Diderot - Paris 7 (UPD7)-Centre National de la Recherche Scientifique (CNRS), Konkoly Observatory, Research Centre for Astronomy and Earth Sciences [Budapest], Hungarian Academy of Sciences (MTA)-Hungarian Academy of Sciences (MTA), Anglo-Australian Observatory (AAO), Okayama Astrophysical Observatory (OAO), National Astronomical Observatory of Japan (NAOJ), Global Edge Institute, Tokyo Institute of Technology [Tokyo] (TITECH), Thüringer Landessternwarte Tautenburg (TLS), Laboratoire de Cosmologie, Astrophysique Stellaire & Solaire, de Planétologie et de Mécanique des Fluides (CASSIOPEE), Université Nice Sophia Antipolis (1965 - 2019) (UNS), COMUE Université Côte d'Azur (2015-2019) (COMUE UCA)-COMUE Université Côte d'Azur (2015-2019) (COMUE UCA)-Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire de la Côte d'Azur, COMUE Université Côte d'Azur (2015-2019) (COMUE UCA)-Université Côte d'Azur (UCA)-Université Côte d'Azur (UCA)-Centre National de la Recherche Scientifique (CNRS), Observatoire de Haute-Provence (OHP), Institut Pythéas (OSU PYTHEAS), Institut de Recherche pour le Développement (IRD)-Aix Marseille Université (AMU)-Institut national de recherche en sciences et technologies pour l'environnement et l'agriculture (IRSTEA)-Centre National de la Recherche Scientifique (CNRS)-Institut de Recherche pour le Développement (IRD)-Aix Marseille Université (AMU)-Institut national de recherche en sciences et technologies pour l'environnement et l'agriculture (IRSTEA)-Centre National de la Recherche Scientifique (CNRS), HELIOS - LATMOS, Université de Versailles Saint-Quentin-en-Yvelines (UVSQ)-Université Pierre et Marie Curie - Paris 6 (UPMC)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS)-Université de Versailles Saint-Quentin-en-Yvelines (UVSQ)-Université Pierre et Marie Curie - Paris 6 (UPMC)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS), Centro di Ateneo di Studi e Attività Spaziali 'Giuseppe Colombo' (CISAS), Università degli Studi di Padova = University of Padua (Unipd), INAF - Osservatorio Astronomico di Padova (OAPD), INAF - Osservatorio Astronomico di Capodimonte (OAC), Department of Physics and Astronomy [Uppsala], Uppsala University, European Southern Observatory (ESO), Institute of Astronomy [Leuven], Catholic University of Leuven - Katholieke Universiteit Leuven (KU Leuven), Observatoire Astronomique de l'Université de Genève (ObsGE), Université de Genève = University of Geneva (UNIGE), University of New South Wales [Sydney] (UNSW), McDonald Observatory, University of Texas at Austin [Austin], High Altitude Observatory (HAO), National Center for Atmospheric Research [Boulder] (NCAR), Landessternwarte Königstuhl [ZAH] (LSW), Universität Heidelberg [Heidelberg] = Heidelberg University, Sydney Institute for Astronomy ( SIfA ), The University of Sydney [Sydney], Danish AsteroSeismology Centre ( DASC ), Centro de Astrofísica da Universidade do Porto ( CAUP ), Universidade do Porto [Porto], Institut d'astrophysique spatiale ( IAS ), Université Paris-Sud - Paris 11 ( UP11 ) -Institut national des sciences de l'Univers ( INSU - CNRS ) -Centre National de la Recherche Scientifique ( CNRS ), INAF - Osservatorio Astrofisico di Catania ( OACT ), Istituto Nazionale di Astrofisica ( INAF ), Département d'Astrophysique, de physique des Particules, de physique Nucléaire et de l'Instrumentation Associée ( DAPNIA ), Commissariat à l'énergie atomique et aux énergies alternatives ( CEA ), Laboratoire Atmosphères, Milieux, Observations Spatiales ( LATMOS ), Université de Versailles Saint-Quentin-en-Yvelines ( UVSQ ) -Université Pierre et Marie Curie - Paris 6 ( UPMC ) -Institut national des sciences de l'Univers ( INSU - CNRS ) -Centre National de la Recherche Scientifique ( CNRS ), Observatoire de Paris - Site de Paris ( OP ), Institut national des sciences de l'Univers ( INSU - CNRS ) -Observatoire de Paris-Centre National de la Recherche Scientifique ( CNRS ), Laboratoire d'études spatiales et d'instrumentation en astrophysique ( LESIA ), Université Pierre et Marie Curie - Paris 6 ( UPMC ) -Institut national des sciences de l'Univers ( INSU - CNRS ) -Observatoire de Paris-Université Paris Diderot - Paris 7 ( UPD7 ) -Centre National de la Recherche Scientifique ( CNRS ), Carnegie Institution for Science [Washington], Astrophysique Interactions Multi-échelles ( AIM - UMR 7158 - UMR E 9005 ), Commissariat à l'énergie atomique et aux énergies alternatives ( CEA ) -Institut national des sciences de l'Univers ( INSU - CNRS ) -Centre National de la Recherche Scientifique ( CNRS ) -Université Paris Diderot - Paris 7 ( UPD7 ), Hungarian Academy of Sciences [Budapest], Anglo-Australian Observatory ( AAO ), Okayama Astrophysical Observatory ( OAO ), National Astronomical Observatory of Japan ( NAOJ ), National Astronomical Observatory of Japan, National Institutes of Natural Sciences, Tokyo Institute of Technology [Tokyo] ( TITECH ), Thüringer Landessternwarte Tautenburg ( TLS ), Laboratoire de Cosmologie, Astrophysique Stellaire & Solaire, de Planétologie et de Mécanique des Fluides ( CASSIOPEE ), Université Nice Sophia Antipolis ( UNS ), Université Côte d'Azur ( UCA ) -Université Côte d'Azur ( UCA ) -Institut national des sciences de l'Univers ( INSU - CNRS ) -Observatoire de la Côte d'Azur, Université Côte d'Azur ( UCA ) -Centre National de la Recherche Scientifique ( CNRS ), Observatoire de Haute-Provence ( OHP ), Institut Pythéas ( OSU PYTHEAS ), Institut national de recherche en sciences et technologies pour l'environnement et l'agriculture ( IRSTEA ) -Institut de Recherche pour le Développement ( IRD ) -Aix Marseille Université ( AMU ) -Centre National de la Recherche Scientifique ( CNRS ) -Institut national de recherche en sciences et technologies pour l'environnement et l'agriculture ( IRSTEA ) -Institut de Recherche pour le Développement ( IRD ) -Aix Marseille Université ( AMU ) -Centre National de la Recherche Scientifique ( CNRS ), HEPPI - LATMOS, Université de Versailles Saint-Quentin-en-Yvelines ( UVSQ ) -Université Pierre et Marie Curie - Paris 6 ( UPMC ) -Institut national des sciences de l'Univers ( INSU - CNRS ) -Centre National de la Recherche Scientifique ( CNRS ) -Université de Versailles Saint-Quentin-en-Yvelines ( UVSQ ) -Université Pierre et Marie Curie - Paris 6 ( UPMC ) -Institut national des sciences de l'Univers ( INSU - CNRS ) -Centre National de la Recherche Scientifique ( CNRS ), Centro di Ateneo di Studi e Attività Spaziali 'Giuseppe Colombo' ( CISAS ), Universita degli Studi di Padova = University of Padua = Université de Padoue, INAF - Osservatorio Astronomico di Padova ( OAPD ), INAF - Osservatorio Astronomico di Capodimonte ( OAC ), European Southern Observatory ( ESO ), Katholieke Universiteit Leuven ( KU Leuven ), Observatoire Astronomique de l'Université de Genève ( ObsGE ), Université de Genève ( UNIGE ), University of New South Wales [Sydney] ( UNSW ), High Altitude Observatory ( HAO ), National Center for Atmospheric Research [Boulder] ( NCAR ), Landessternwarte Königstuhl [ZAH] ( LSW ), Universität Heidelberg [Heidelberg], Université Paris-Sud - Paris 11 (UP11)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS), Centre National de la Recherche Scientifique (CNRS)-Observatoire de Paris, PSL Research University (PSL)-PSL Research University (PSL)-Institut national des sciences de l'Univers (INSU - CNRS), Centre National de la Recherche Scientifique (CNRS)-Université Paris Diderot - Paris 7 (UPD7)-Observatoire de Paris, PSL Research University (PSL)-PSL Research University (PSL)-Institut national des sciences de l'Univers (INSU - CNRS)-Université Pierre et Marie Curie - Paris 6 (UPMC), Astrophysique Interprétation Modélisation (AIM (UMR_7158 / UMR_E_9005 / UM_112)), Université Nice Sophia Antipolis (... - 2019) (UNS), Université Côte d'Azur (UCA)-Université Côte d'Azur (UCA)-Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire de la Côte d'Azur, Université Côte d'Azur (UCA)-Centre National de la Recherche Scientifique (CNRS), Aix Marseille Université (AMU)-Centre National de la Recherche Scientifique (CNRS)-Institut national de recherche en sciences et technologies pour l'environnement et l'agriculture (IRSTEA)-Institut de Recherche pour le Développement (IRD)-Aix Marseille Université (AMU)-Centre National de la Recherche Scientifique (CNRS)-Institut national de recherche en sciences et technologies pour l'environnement et l'agriculture (IRSTEA)-Institut de Recherche pour le Développement (IRD), Universita degli Studi di Padova, Université de Genève (UNIGE), Universidade do Porto, Centre National de la Recherche Scientifique (CNRS)-Institut national des sciences de l'Univers (INSU - CNRS)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Université Paris Diderot - Paris 7 (UPD7), and Université Côte d'Azur (UCA)-COMUE Université Côte d'Azur (2015-2019) (COMUE UCA)-Université Côte d'Azur (UCA)-Centre National de la Recherche Scientifique (CNRS)
Subjects: Offset (computer science), Oscillations, Granulation, FOS: Physical sciences, Lifetimes, Astrophysics, 01 natural sciences, Asteroseismology, Stellar Oscillations, Photometry, P-Modes, 0103 physical sciences, Solar-like oscillations, 010303 astronomy & astrophysics, Solar and Stellar Astrophysics (astro-ph.SR), Physics, geography, [ PHYS.ASTR.SR ] Physics [physics]/Astrophysics [astro-ph]/Solar and Stellar Astrophysics [astro-ph.SR], geography.geographical_feature_category, 010308 nuclear & particles physics, [SDU.ASTR.SR]Sciences of the Universe [physics]/Astrophysics [astro-ph]/Solar and Stellar Astrophysics [astro-ph.SR], Procyon A, Multi site, Sun, Spectral density, Centroid, Astronomy and Astrophysics, [PHYS.ASTR.SR]Physics [physics]/Astrophysics [astro-ph]/Solar and Stellar Astrophysics [astro-ph.SR], Stars, Corot, Data Reduction, Astrophysics - Solar and Stellar Astrophysics, Space and Planetary Science, Ridge, stars: oscillations, stars: individual (Procyon A), [ SDU.ASTR.SR ] Sciences of the Universe [physics]/Astrophysics [astro-ph]/Solar and Stellar Astrophysics [astro-ph.SR]
Abstract: We have analyzed data from a multi-site campaign to observe oscillations in the F5 star Procyon. The data consist of high-precision velocities that we obtained over more than three weeks with eleven telescopes. A new method for adjusting the data weights allows us to suppress the sidelobes in the power spectrum. Stacking the power spectrum in a so-called echelle diagram reveals two clear ridges that we identify with even and odd values of the angular degree (l=0 and 2, and l=1 and 3, respectively). We interpret a strong, narrow peak at 446 muHz that lies close to the l=1 ridge as a mode with mixed character. We show that the frequencies of the ridge centroids and their separations are useful diagnostics for asteroseismology. In particular, variations in the large separation appear to indicate a glitch in the sound-speed profile at an acoustic depth of about 1000 s. We list frequencies for 55 modes extracted from the data spanning 20 radial orders, a range comparable to the best solar data, which will provide valuable constraints for theoretical models. A preliminary comparison with published models shows that the offset between observed and calculated frequencies for the radial modes is very different for Procyon than for the Sun and other cool stars. We find the mean lifetime of the modes in Procyon to be 1.29 +0.55/-0.49 days, which is significantly shorter than the 2-4 days seen in the Sun., Comment: accepted for publication in ApJ
Published: 2010

21. New values of gravitational moments J2 and J4 deduced from helioseismology

Author: R. Mecheri, Abdanour Irbah, Gabrielle Berthomieu, Janine Provost, Toufik E. Abdelatif, Centre de Recherche en Astronomie Astrophysique et Géophysique (CRAAG), Laboratoire de Cosmologie, Astrophysique Stellaire & Solaire, de Planétologie et de Mécanique des Fluides (CASSIOPEE), Université Nice Sophia Antipolis (... - 2019) (UNS), COMUE Université Côte d'Azur (2015-2019) (COMUE UCA)-COMUE Université Côte d'Azur (2015-2019) (COMUE UCA)-Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire de la Côte d'Azur, and Université Côte d'Azur (UCA)-COMUE Université Côte d'Azur (2015-2019) (COMUE UCA)-Université Côte d'Azur (UCA)-Centre National de la Recherche Scientifique (CNRS)
Subjects: [PHYS.ASTR.IM]Physics [physics]/Astrophysics [astro-ph]/Instrumentation and Methods for Astrophysic [astro-ph.IM], FOS: Physical sciences, Rotation, 01 natural sciences, 0103 physical sciences, Differential rotation, Astrophysics::Solar and Stellar Astrophysics, Helioseismology, 010303 astronomy & astrophysics, Stellar evolution, Instrumentation and Methods for Astrophysics (astro-ph.IM), Solar and Stellar Astrophysics (astro-ph.SR), Physics, Standard solar model, [SDU.ASTR.SR]Sciences of the Universe [physics]/Astrophysics [astro-ph]/Solar and Stellar Astrophysics [astro-ph.SR], 010308 nuclear & particles physics, Astronomy and Astrophysics, [PHYS.ASTR.SR]Physics [physics]/Astrophysics [astro-ph]/Solar and Stellar Astrophysics [astro-ph.SR], [SDU.ASTR.IM]Sciences of the Universe [physics]/Astrophysics [astro-ph]/Instrumentation and Methods for Astrophysic [astro-ph.IM], Computational physics, Stars, Astrophysics - Solar and Stellar Astrophysics, Space and Planetary Science, Moment (physics), Quadrupole, Physics::Space Physics, Astrophysics::Earth and Planetary Astrophysics, Astrophysics - Instrumentation and Methods for Astrophysics
Abstract: International audience; By applying the theory of slowly rotating stars to the Sun, the solar quadrupole and octopole moments J2 and J4 were computed using a solar model obtained from CESAM stellar evolution code (Morel, 1997) combined with a recent model of solar differential rotation deduced from helioseismology (Corbard et al., 2002). This model takes into account a near-surface radial gradient of rotation which was inferred and quantified from MDI f-mode observations by Corbard and Thompson (2002). The effect of this observational near-surface gradient on the theoretical values of the surface parameters J2, J4 is investigated. The results show that the octopole moment J4 is much more sensitive than the quadrupole moment J2 to the subsurface radial gradient of rotation.
Published: 2009
Full Text: View/download PDF

22. The quest for the solar g modes

Author: William J. Chaplin, A. H. Gabriel, Sylvaine Turck-Chièze, F. Baudin, Günter Houdek, Patrick Boumier, B. N. Andersen, Alexander G. Kosovichev, Wolfgang Finsterle, Takashi Sekii, Antonio Jiménez, Yvonne Elsworth, Rafael A. García, A. M. Broomhall, T. Toutain, Claus Fröhlich, G. Grec, T. Appourchaux, Janine Provost, Kevin Belkacem, Douglas Gough, Laboratoire de Cosmologie, Astrophysique Stellaire & Solaire, de Planétologie et de Mécanique des Fluides (CASSIOPEE), Université Nice Sophia Antipolis (... - 2019) (UNS), COMUE Université Côte d'Azur (2015-2019) (COMUE UCA)-COMUE Université Côte d'Azur (2015-2019) (COMUE UCA)-Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire de la Côte d'Azur, and Université Côte d'Azur (UCA)-COMUE Université Côte d'Azur (2015-2019) (COMUE UCA)-Université Côte d'Azur (UCA)-Centre National de la Recherche Scientifique (CNRS)
Subjects: Physics, Buoyancy, 010504 meteorology & atmospheric sciences, Structure (category theory), FOS: Physical sciences, Astronomy and Astrophysics, Astrophysics, engineering.material, Eigenfunction, 01 natural sciences, Core (optical fiber), Theoretical physics, Amplitude, Solar core, Convection zone, Astrophysics - Solar and Stellar Astrophysics, 13. Climate action, Space and Planetary Science, 0103 physical sciences, engineering, Restoring force, 010303 astronomy & astrophysics, Solar and Stellar Astrophysics (astro-ph.SR), 0105 earth and related environmental sciences
Abstract: Solar gravity modes (or g modes) -- oscillations of the solar interior for which buoyancy acts as the restoring force -- have the potential to provide unprecedented inference on the structure and dynamics of the solar core, inference that is not possible with the well observed acoustic modes (or p modes). The high amplitude of the g-mode eigenfunctions in the core and the evanesence of the modes in the convection zone make the modes particularly sensitive to the physical and dynamical conditions in the core. Owing to the existence of the convection zone, the g modes have very low amplitudes at photospheric levels, which makes the modes extremely hard to detect. In this paper, we review the current state of play regarding attempts to detect g modes. We review the theory of g modes, including theoretical estimation of the g-mode frequencies, amplitudes and damping rates. Then we go on to discuss the techniques that have been used to try to detect g modes. We review results in the literature, and finish by looking to the future, and the potential advances that can be made -- from both data and data-analysis perspectives -- to give unambiguous detections of individual g modes. The review ends by concluding that, at the time of writing, there is indeed a consensus amongst the authors that there is currently no undisputed detection of solar g modes., Comment: 71 pages, 18 figures, accepted by Astronomy and Astrophysics Review
Published: 2009
Full Text: View/download PDF

23. The asymptotic spectrum of gravity modes as a function of the solar structure: Standard solar model

Author: Janine Provost and Gabrielle Berthomieu
Subjects: Physics, Standard solar model, Gravity (chemistry), Classical mechanics, Gravitational field, Space and Planetary Science, Gravitational wave, Solar rotation, Astronomy and Astrophysics, Stellar structure, Function (mathematics), Solar physics, Computational physics
Abstract: Some results are given on the properties of the second-order asymptotic expression of the periods of low-degree gravity modes and on their rotational splitting. These could be of some help for the detection of these modes in the signal.
Published: 1991

24. About solar model calibration

Author: Janine Provost, Yveline Lebreton, Gabrielle Berthomieu, and Pierre Morel
Subjects: Physics, Standard solar model, Hydrogen, Oscillation, Solar neutrino, Flux, chemistry.chemical_element, Astrophysics, Computational physics, Standard Model, Convection zone, chemistry, Physics::Space Physics, Calibration, Astrophysics::Solar and Stellar Astrophysics, Astrophysics::Earth and Planetary Astrophysics
Abstract: A new value of the ratio of the heavy elements content to hydrogen abundance Z/X has been recently estimated in the solar atmosphere. We present the consequences of this result on the solar standard model and we examine the sensitivity to Z/X of the solar neutrinos flux predictions and of the oscillation frequencies.
Published: 2008

25. Update on g-mode research

Author: Janine Provost, Antonio Jiménez, S. J. Jiménez-Reyes, Savita Mathur, Rafael A. García, Jérôme Ballot, Sylvaine Turck-Chièze, Antonio Eff-Darwich, Pere L. Palle, Laboratoire de Cosmologie, Astrophysique Stellaire & Solaire, de Planétologie et de Mécanique des Fluides (CASSIOPEE), Université Nice Sophia Antipolis (... - 2019) (UNS), COMUE Université Côte d'Azur (2015-2019) (COMUE UCA)-COMUE Université Côte d'Azur (2015-2019) (COMUE UCA)-Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire de la Côte d'Azur, and Université Côte d'Azur (UCA)-COMUE Université Côte d'Azur (2015-2019) (COMUE UCA)-Université Côte d'Azur (UCA)-Centre National de la Recherche Scientifique (CNRS)
Subjects: Physics, Gravity (chemistry), 010504 meteorology & atmospheric sciences, Astrophysics (astro-ph), Mode (statistics), FOS: Physical sciences, Astronomy and Astrophysics, Astrophysics, Space (mathematics), Rotation, 01 natural sciences, Measure (mathematics), Dipole, Quality (physics), Amplitude, Space and Planetary Science, 0103 physical sciences, 010303 astronomy & astrophysics, 0105 earth and related environmental sciences
Abstract: Since the beginning of this century we have attended a blooming of the gravity-mode research thanks to the unprecedented quality of the data available, either from space with SoHO, or from the ground-based networks as BiSON or GONG. From the first upper limit of the gravity-mode amplitudes fixed at 10 mm/s at 200 microHz given by Appourchaux et al. (2000), on one hand, a peak was supposed to be a component of the l=1, n=1 mixed mode (Garcia et al. 2001a, b; Gabriel et al. 2002) and, on the other hand, a couple of patterns --multiplets-- were attributed to gravity modes (Turck-Chieze et al. 2004; Mathur et al. 2007). One of these patterns, found around 220 microHz, could be labeled as the l=2, n =-3 g mode, which is expected to be the one with the highest surface amplitude (Cox and Guzik 2004). Finally, in 2007, Garcia et al. were able to measure the fingertips of the dipole gravity modes looking for their asymptotic properties. In the present paper we present an update of the recent developments on this subject with special attention to the 220 microHz region, the dipole asymptotic properties and the impact of the incoming g-mode observations on the knowledge of the solar structure and rotation profile., Comment: Paper accepted for publication in Astronomische Nachrichten. 9 pages, 8 figures
Published: 2008
Full Text: View/download PDF

26. NOSC: Nice OScillations Code

Author: Janine Provost, Laboratoire de Cosmologie, Astrophysique Stellaire & Solaire, de Planétologie et de Mécanique des Fluides (CASSIOPEE), Université Nice Sophia Antipolis (... - 2019) (UNS), COMUE Université Côte d'Azur (2015-2019) (COMUE UCA)-COMUE Université Côte d'Azur (2015-2019) (COMUE UCA)-Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire de la Côte d'Azur, and Université Côte d'Azur (UCA)-COMUE Université Côte d'Azur (2015-2019) (COMUE UCA)-Université Côte d'Azur (UCA)-Centre National de la Recherche Scientifique (CNRS)
Subjects: Physics, 010504 meteorology & atmospheric sciences, Nice, Astronomy and Astrophysics, Astrophysics, 01 natural sciences, Asteroseismology, Space and Planetary Science, Internal consistency, 0103 physical sciences, Code (cryptography), Applied mathematics, Adiabatic process, 010303 astronomy & astrophysics, computer, 0105 earth and related environmental sciences, computer.programming_language
Abstract: A short presentation of the Nice OScillations Code (NOSC) and of its general properties is given here. We described the physics and the various numerical tools, that we have developed to check the validity and the internal consistency of the frequency calculations for a given model. We present different examples of adiabatic calculations, with an estimation of the achieved internal consistency and numerical accuracy.
Published: 2008

27. CoRoT measures solar-like oscillations and granulation in stars hotter than the Sun

Author: Yveline Lebreton, Ignasi Ribas, Marie-Jo Goupil, C. Catala, Sylvie Vauclair, Philippe Mathias, Coralie Neiner, Malcolm Fridlund, R. Garrido, J. Ballot, Michel Rieutord, Patrick Boumier, Marc-Antoine Dupret, Werner W. Weiss, Conny Aerts, Gabrielle Berthomieu, G. Vauclair, Annie Baglin, Stéphane Charpinet, Frédéric Baudin, R. Samadi, T. Toutain, Eduardo Janot-Pacheco, Rafael A. García, Ian W. Roxburgh, Konstanze Zwintz, Didier Tiphène, M. Auvergne, Thierry Appourchaux, Anne-Marie Hubert, Sylvaine Turck-Chièze, B. Mosser, François Lignières, Eric Michel, Mário J. P. F. G. Monteiro, Caroline Barban, A. Grotsch-Noels, Hans Kjeldsen, G. Alecian, Janine Provost, José Renan de Medeiros, Teodoro Roca Cortés, Anne Thoul, Ennio Poretti, Faculdade de Ciências, Laboratoire d'études spatiales et d'instrumentation en astrophysique (LESIA), Université Pierre et Marie Curie - Paris 6 (UPMC)-Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire de Paris, Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Université Paris Diderot - Paris 7 (UPD7)-Centre National de la Recherche Scientifique (CNRS), Laboratoire Astrophysique de Toulouse-Tarbes (LATT), Université Toulouse III - Paul Sabatier (UT3), Université Fédérale Toulouse Midi-Pyrénées-Université Fédérale Toulouse Midi-Pyrénées-Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire Midi-Pyrénées (OMP), Météo France-Centre National d'Études Spatiales [Toulouse] (CNES)-Université Fédérale Toulouse Midi-Pyrénées-Centre National de la Recherche Scientifique (CNRS)-Institut de Recherche pour le Développement (IRD)-Météo France-Centre National d'Études Spatiales [Toulouse] (CNES)-Centre National de la Recherche Scientifique (CNRS)-Institut de Recherche pour le Développement (IRD)-Centre National de la Recherche Scientifique (CNRS), Université de Toulouse (UT)-Université de Toulouse (UT)-Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire Midi-Pyrénées (OMP), Institut de Recherche pour le Développement (IRD)-Université Toulouse III - Paul Sabatier (UT3), and Université de Toulouse (UT)-Université de Toulouse (UT)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National d'Études Spatiales [Toulouse] (CNES)-Centre National de la Recherche Scientifique (CNRS)-Météo-France -Institut de Recherche pour le Développement (IRD)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National d'Études Spatiales [Toulouse] (CNES)-Centre National de la Recherche Scientifique (CNRS)-Météo-France -Centre National de la Recherche Scientifique (CNRS)
Subjects: Convection, Astronomy, FOS: Physical sciences, Astrophysics, Astrophysics::Cosmology and Extragalactic Astrophysics, Rotation, 01 natural sciences, Asteroseismology, Solar-Like Oscillations, 0103 physical sciences, Astrophysics::Solar and Stellar Astrophysics, Stars hotter than the sun, Solar-like oscillations, Helioseismology, 010303 astronomy & astrophysics, Astrophysics::Galaxy Astrophysics, Physics, Multidisciplinary, Astrofísica, Ciências Físicas, Astronomia, 010308 nuclear & particles physics, Oscillation, Astrophysics (astro-ph), Astrophysics, Physical sciences, Astronomy, CoRoT (Convection Rotation and Planetary Transits) satellite, Stars, Stellar granulation, ComputingMethodologies_DOCUMENTANDTEXTPROCESSING, [SDU.ASTR.GA]Sciences of the Universe [physics]/Astrophysics [astro-ph]/Galactic Astrophysics [astro-ph.GA], Astrophysics::Earth and Planetary Astrophysics, Main sequence
Abstract: 4 pages, 3 figures.-- Supporting Online Material: Text, Fig. S1, Table S1 and References, available at: http://www.sciencemag.org/cgi/content/full/322/5901/558/DC1, Oscillations of the Sun have been used to understand its interior structure. The extension of similar studies to more distant stars has raised many difficulties despite the strong efforts of the international community over the past decades. The CoRoT (Convection Rotation and Planetary Transits) satellite, launched in December 2006, has now measured oscillations and the stellar granulation signature in three main sequence stars that are noticeably hotter than the sun. The oscillation amplitudes are about 1.5 times as large as those in the Sun; the stellar granulation is up to three times as high. The stellar amplitudes are about 25% below the theoretic values, providing a measurement of the nonadiabaticity of the process ruling the oscillations in the outer layers of the stars.
Published: 2008

28. A multisite campaign to measure solar-like oscillations in Procyon. I. Observations, data reduction, and slow variations

Author: François Bouchy, Jerome Schmitt, Fabien Carrier, Thierry Appourchaux, M. Martic, Riccardo Claudi, Michael Bazot, Serena Benatti, Benoit Mosser, Danuta Sosnowska, Jean-Loup Bertaux, L. Glowienka, Hans Bruntt, Caroline Barban, Simon J. O'Toole, Timothy R. Bedding, Rafael A. García, Artie P. Hatzes, Karsten Brogaard, Eiji Kambe, Michael Endl, Silvio Leccia, Patrick Eggenberger, Janine Provost, Hans Kjeldsen, S. Frandsen, Torben Arentoft, Sylvaine Turck-Chièze, Eric Stempels, Travis S. Metcalfe, László L. Kiss, T. H. Dall, Bun'ei Sato, Hideyuki Izumiura, Gabrielle Berthomieu, R. Paul Butler, M. Hartmann, Eric Michel, Joergen Christensen-Dalsgaard, Frank Grundahl, Sabine Reffert, Rosario Cosentino, Saskia Hekker, Hiroyasu Ando, Alfio Bonanno, Christoffer Karoff, Robert A. Wittenmyer, J. C. Lebrun, Danish AsteroSeismology Centre (DASC), Aarhus University [Aarhus], Sydney Institute for Astronomy (SIfA), The University of Sydney, Centro de Astrofísica da Universidade do Porto (CAUP), Universidade do Porto = University of Porto, Gemini Observatory [Southern Operations Center], Association of Universities for Research in Astronomy (AURA), Instituut voor Sterrenkunde [Leuven], Catholic University of Leuven - Katholieke Universiteit Leuven (KU Leuven), Observatoire Astronomique de l'Université de Genève (ObsGE), Université de Genève = University of Geneva (UNIGE), EPFL Laboratoire d’astrophysique, Ecole Polytechnique Fédérale de Lausanne (EPFL), McDonald Observatory, University of Texas at Austin [Austin], High Altitude Observatory (HAO), National Center for Atmospheric Research [Boulder] (NCAR), Leiden Observatory [Leiden], Universiteit Leiden, Royal Observatory of Belgium [Brussels] (ROB), Landessternwarte Königstuhl [ZAH] (LSW), Universität Heidelberg [Heidelberg] = Heidelberg University, Department of Terrestrial Magnetism [Carnegie Institution], Carnegie Institution for Science, Anglo-Australian Observatory (AAO), Okayama Astrophysical Observatory (OAO), National Astronomical Observatory of Japan (NAOJ), Global Edge Institute, Tokyo Institute of Technology [Tokyo] (TITECH), Thüringer Landessternwarte Tautenburg (TLS), Institut d'Astrophysique de Paris (IAP), Université Pierre et Marie Curie - Paris 6 (UPMC)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS), Observatoire de Paris - Site de Paris (OP), Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire de Paris, Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Centre National de la Recherche Scientifique (CNRS), Laboratoire d'études spatiales et d'instrumentation en astrophysique (LESIA), Université Pierre et Marie Curie - Paris 6 (UPMC)-Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire de Paris, Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Université Paris Diderot - Paris 7 (UPD7)-Centre National de la Recherche Scientifique (CNRS), Institut d'astrophysique spatiale (IAS), Université Paris-Sud - Paris 11 (UP11)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS)-Centre National d’Études Spatiales [Paris] (CNES), Laboratoire de Cosmologie, Astrophysique Stellaire & Solaire, de Planétologie et de Mécanique des Fluides (CASSIOPEE), Université Nice Sophia Antipolis (1965 - 2019) (UNS), COMUE Université Côte d'Azur (2015-2019) (COMUE UCA)-COMUE Université Côte d'Azur (2015-2019) (COMUE UCA)-Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire de la Côte d'Azur, COMUE Université Côte d'Azur (2015-2019) (COMUE UCA)-Université Côte d'Azur (UCA)-Université Côte d'Azur (UCA)-Centre National de la Recherche Scientifique (CNRS), Département d'Astrophysique, de physique des Particules, de physique Nucléaire et de l'Instrumentation Associée (DAPNIA), Commissariat à l'énergie atomique et aux énergies alternatives (CEA), Service d'aéronomie (SA), Université de Versailles Saint-Quentin-en-Yvelines (UVSQ)-Université Pierre et Marie Curie - Paris 6 (UPMC)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS), Observatoire de Haute-Provence (OHP), Institut Pythéas (OSU PYTHEAS), Institut de Recherche pour le Développement (IRD)-Aix Marseille Université (AMU)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS)-Institut National de Recherche pour l’Agriculture, l’Alimentation et l’Environnement (INRAE)-Institut de Recherche pour le Développement (IRD)-Aix Marseille Université (AMU)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS)-Institut National de Recherche pour l’Agriculture, l’Alimentation et l’Environnement (INRAE), INAF - Osservatorio Astrofisico di Catania (OACT), Istituto Nazionale di Astrofisica (INAF), INAF - Osservatorio Astronomico di Padova (OAPD), INAF - Osservatorio Astronomico di Capodimonte (OAC), SUPA School of Physics and Astronomy [University of St Andrews], University of St Andrews [Scotland]-Scottish Universities Physics Alliance (SUPA), Universidade do Porto, Université de Genève (UNIGE), Universiteit Leiden [Leiden], Universität Heidelberg [Heidelberg], Carnegie Institution for Science [Washington], Centre National de la Recherche Scientifique (CNRS)-Institut national des sciences de l'Univers (INSU - CNRS)-Université Pierre et Marie Curie - Paris 6 (UPMC), Université Paris-Sud - Paris 11 (UP11)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS), Université Nice Sophia Antipolis (... - 2019) (UNS), and Université Côte d'Azur (UCA)-COMUE Université Côte d'Azur (2015-2019) (COMUE UCA)-Université Côte d'Azur (UCA)-Centre National de la Recherche Scientifique (CNRS)
Subjects: Physics, 010504 meteorology & atmospheric sciences, [SDU.ASTR]Sciences of the Universe [physics]/Astrophysics [astro-ph], Stellar rotation, Astrophysics (astro-ph), FOS: Physical sciences, Astronomy and Astrophysics, Astrophysics, 01 natural sciences, Radial velocity, Stars, Amplitude, Space and Planetary Science, 0103 physical sciences, Modulation (music), Astrophysics::Solar and Stellar Astrophysics, Solar-like oscillations, Astrophysics::Earth and Planetary Astrophysics, Variation (astronomy), 010303 astronomy & astrophysics, 0105 earth and related environmental sciences, Data reduction
Abstract: We have carried out a multi-site campaign to measure oscillations in the F5 star Procyon A. We obtained high-precision velocity observations over more than three weeks with eleven telescopes, with almost continuous coverage for the central ten days. This represents the most extensive campaign so far organized on any solar-type oscillator. We describe in detail the methods we used for processing and combining the data. These involved calculating weights for the velocity time series from the measurement uncertainties and adjusting them in order to minimize the noise level of the combined data. The time series of velocities for Procyon shows the clear signature of oscillations, with a plateau of excess power that is centred at 0.9 mHz and is broader than has been seen for other stars. The mean amplitude of the radial modes is 38.1 +/- 1.3 cm/s (2.0 times solar), which is consistent with previous detections from the ground and by the WIRE spacecraft, and also with the upper limit set by the MOST spacecraft. The variation of the amplitude during the observing campaign allows us to estimate the mode lifetime to be 1.5 d (+1.9/-0.8 d). We also find a slow variation in the radial velocity of Procyon, with good agreement between different telescopes. These variations are remarkably similar to those seen in the Sun, and we interpret them as being due to rotational modulation from active regions on the stellar surface. The variations appear to have a period of about 10 days, which presumably equals the stellar rotation period or, perhaps, half of it. The amount of power in these slow variations indicates that the fractional area of Procyon covered by active regions is slightly higher than for the Sun., accepted for publication in ApJ. Minor change to Fig 11
Published: 2008

29. The CoRoT evolution and seismic tools activity. Goals and Tasks

Author: Yveline Lebreton, M. J. Goupil, Janine Provost, Josefina Montalbán, A. Moya, Esta Team, Ian W. Roxburgh, Annie Baglin, Jørgen Christensen-Dalsgaard, Richard Scuflaire, Mário J. P. F. G. Monteiro, Eric Michel, Institut de Physique de Rennes (IPR), Université de Rennes (UR)-Centre National de la Recherche Scientifique (CNRS), Centro de Astrofísica da Universidade do Porto (CAUP), Universidade do Porto = University of Porto, Département des Sciences et Gestion de l'Environnement/Océanologie [Liège], Université de Liège, Danish AsteroSeismology Centre (DASC), Aarhus University [Aarhus], Laboratoire des Sciences du Climat et de l'Environnement [Gif-sur-Yvette] (LSCE), Université de Versailles Saint-Quentin-en-Yvelines (UVSQ)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Institut national des sciences de l'Univers (INSU - CNRS)-Université Paris-Saclay-Centre National de la Recherche Scientifique (CNRS), Department of Computer Science (Queen Mary University of London), Queen Mary University of London (QMUL), the European Helio- and Asteroseismology Network (HELAS), the European Commission's Sixth Framework Programme, Université de Rennes 1 (UR1), Université de Rennes (UNIV-RENNES)-Université de Rennes (UNIV-RENNES)-Centre National de la Recherche Scientifique (CNRS), Universidade do Porto, Institut national des sciences de l'Univers (INSU - CNRS)-Université Paris-Saclay-Centre National de la Recherche Scientifique (CNRS)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Université de Versailles Saint-Quentin-en-Yvelines (UVSQ), Laboratoire de Cosmologie, Astrophysique Stellaire & Solaire, de Planétologie et de Mécanique des Fluides (CASSIOPEE), Université Nice Sophia Antipolis (... - 2019) (UNS), COMUE Université Côte d'Azur (2015-2019) (COMUE UCA)-COMUE Université Côte d'Azur (2015-2019) (COMUE UCA)-Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire de la Côte d'Azur, and Université Côte d'Azur (UCA)-COMUE Université Côte d'Azur (2015-2019) (COMUE UCA)-Université Côte d'Azur (UCA)-Centre National de la Recherche Scientifique (CNRS)
Subjects: [PHYS.ASTR.IM]Physics [physics]/Astrophysics [astro-ph]/Instrumentation and Methods for Astrophysic [astro-ph.IM], media_common.quotation_subject, 97.10.Cv, 97.10.Sj, 95.75.Pq, FOS: Physical sciences, Context (language use), Astrophysics, 01 natural sciences, Asteroseismology, Space exploration, Task (project management), Numerical precision, Presentation, 0103 physical sciences, Stars: oscillations, 010306 general physics, Set (psychology), 010303 astronomy & astrophysics, media_common, Physics, Astrophysics (astro-ph), Astronomy and Astrophysics, [SDU.ASTR.IM]Sciences of the Universe [physics]/Astrophysics [astro-ph]/Instrumentation and Methods for Astrophysic [astro-ph.IM], Stars: evolution, Space and Planetary Science, Systems engineering, Stars: interiors
Abstract: The forthcoming data expected from space missions such as CoRoT require the capacity of the available tools to provide accurate models whose numerical precision is well above the expected observational errors. In order to secure that these tools meet the specifications, a team has been established to test and, when necessary, to improve the codes available in the community. The CoRoT evolution and seismic tool activity (ESTA) has been set up with this mission. Several groups have been involved. The present paper describes the motivation and the organisation of this activity, providing the context and the basis for the presentation of the results that have been achieved so far. This is not a finished task as future even better data will continue to demand more precise and complete tools for asteroseismology., 11 pages, 3 figures, accepted for publication in Astrophysics and Space Science, 'CoRoT ESTA' special volume
Published: 2008

30. Investigation on numerical accuracy of ZAMS models of one solar mass

Author: Janine Provost, Gabrielle Berthomieu, and P. Morel
Subjects: Physics, Solar mass, Opacity, Astronomy and Astrophysics, Astrophysics, Solar physics, Atmosphere, Space and Planetary Science, Physics::Space Physics, Radiative transfer, Astrophysics::Solar and Stellar Astrophysics, Stellar structure, Astrophysics::Earth and Planetary Astrophysics, Helioseismology, Astrophysics::Galaxy Astrophysics, Interpolation
Abstract: Helioseismology requires solar models computed with great accuracy. Results of investigations about the incidence in ZAMS models of one solar mass of the numerical errors arising from the interpolation of opacity tables and from the integration of the atmosphere are reported.
Published: 1990

31. Non-equidistant spectrum of gravity modes of a solar model with a mixed core

Author: Janine Provost, V. Gavryusev, E. A. Gavryuseva, and Gabrielle Berthomieu
Subjects: Physics, Standard solar model, Meteorology, Space and Planetary Science, Mathematical analysis, Brunt–Väisälä frequency, Stratification (water), Astronomy and Astrophysics, Equidistant, Helioseismology, Solar physics
Abstract: The asymptotic properties of the gravity modes of solar models with a mixed core have been investigated. In this model, the Brunt-Vaissala frequency has a strong enhancement in the region of variable chemical composition at the boundary of the mixed core, giving rise to a non-equidistant spectrum of gravity modes periods. An asymptotic expression for the periods is derived, which relates the main feature of the departure from period equidistance to the stratification of the model. Qualitative agreement with the numerical periods of the model is obtained.
Published: 1990

32. Oscillations in Procyon A: First results from a multi-site campaign

Author: Silvio Leccia, S. Benatti, Caroline Barban, François Bouchy, P. Eggenberger, Saskia Hekker, H. Kjeldsen, Hiroyasu Ando, H. C. Stempels, Simon J. O'Toole, P. A. P. Nghiem, S. Turck-Chiez, A. P. Hatzes, Michael Endl, Jørgen Christensen-Dalsgaard, Frank Grundahl, H. Bruntt, Gabrielle Berthomieu, Timothy R. Bedding, Janine Provost, Christoffer Karoff, T. S. Metcalfe, M. Hartmann, R. Samadi, László L. Kiss, Riccardo Claudi, K. Brogaard, S. A. Bonanno, F. Thévenin, Rosario Cosentino, Rafael A. García, Fabien Carrier, S. Frandsen, Robert A. Wittenmyer, Eiji Kambe, Sabine Reffert, R. P. Butler, Torben Arentoft, T. Appourchaux, E. Michel, T. H. Dall, D. Sosnowska, B. Sato, Hideyuki Izumiura, M. Martic, J. C. Lebrun, Benoit Mosser, M. Bazot, Laboratoire d'études spatiales et d'instrumentation en astrophysique (LESIA), Université Pierre et Marie Curie - Paris 6 (UPMC)-Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire de Paris, Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Université Paris Diderot - Paris 7 (UPD7)-Centre National de la Recherche Scientifique (CNRS), Pôle Astronomie du LESIA, Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Université Paris Diderot - Paris 7 (UPD7)-Centre National de la Recherche Scientifique (CNRS)-Université Pierre et Marie Curie - Paris 6 (UPMC)-Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire de Paris, Pôle Planétologie du LESIA, Laboratoire d'études spatiales et d'instrumentation en astrophysique = Laboratory of Space Studies and Instrumentation in Astrophysics (LESIA), Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire de Paris, Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS)-Université Paris Cité (UPCité)-Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire de Paris, and Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS)-Université Paris Cité (UPCité)
Subjects: Physics, History, Oscillation, Astrophysics (astro-ph), Mode (statistics), FOS: Physical sciences, Astrophysics, Star (graph theory), Span (engineering), Computer Science Applications, Education, Angular diameter, Aliasing, Position (vector), Astrophysics::Solar and Stellar Astrophysics, Binary system, [PHYS.ASTR]Physics [physics]/Astrophysics [astro-ph]
Abstract: Procyon A is a bright F5IV star in a binary system. Although the distance, mass and angular diameter of this star are all known with high precision, the exact evolutionary state is still unclear. Evolutionary tracks with different ages and different mass fractions of hydrogen in the core pass, within the errors, through the observed position of Procyon A in the Hertzsprung-Russell diagram. For more than 15 years several different groups have studied the solar-like oscillations in Procyon A to determine its evolutionary state. Although several studies independently detected power excess in the periodogram, there is no agreement on the actual oscillation frequencies yet. This is probably due to either insufficient high-quality data (i.e., aliasing) or due to intrinsic properties of the star (i.e., short mode lifetimes). Now a spectroscopic multi-site campaign using 10 telescopes world-wide (minimizing aliasing effects) with a total time span of nearly 4 weeks (increase the frequency resolution) is performed to identify frequencies in this star and finally determine its properties and evolutionary state., 7 pages, 4 figures to be published in the proceedings of HELAS II International Conference: Helioseismology, Asteroseismology and MHD Connections published in the Journal of Physics: Conference Series. High resolution colour figures can be provided on request
Published: 2007

33. Sensitivity of low degree oscillations to the change in solar abundances

Author: Pierre Morel, Gabrielle Berthomieu, Thierry Corbard, A. Zaatri, Janine Provost, Laboratoire de Cosmologie, Astrophysique Stellaire & Solaire, de Planétologie et de Mécanique des Fluides (CASSIOPEE), Université Nice Sophia Antipolis (... - 2019) (UNS), COMUE Université Côte d'Azur (2015-2019) (COMUE UCA)-COMUE Université Côte d'Azur (2015-2019) (COMUE UCA)-Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire de la Côte d'Azur, and Université Côte d'Azur (UCA)-COMUE Université Côte d'Azur (2015-2019) (COMUE UCA)-Université Côte d'Azur (UCA)-Centre National de la Recherche Scientifique (CNRS)
Subjects: FOS: Physical sciences, chemistry.chemical_element, Context (language use), Astrophysics, 01 natural sciences, Neon, Solar chemical, Solar core, Abundance (ecology), 0103 physical sciences, Astrophysics::Solar and Stellar Astrophysics, Helioseismology, 010306 general physics, 010303 astronomy & astrophysics, Astrophysics::Galaxy Astrophysics, Physics, integumentary system, Astrophysics (astro-ph), food and beverages, Astronomy and Astrophysics, Abundance of the chemical elements, chemistry, Convection zone, Space and Planetary Science, Physics::Space Physics, Astrophysics::Earth and Planetary Astrophysics
Abstract: Context. The most recent determination of the solar chemical composition, using a time-dependent, 3D hydrodynamical model of the solar atmosphere, exhibits a significant decrease of C, N, O abundances compared to their previous values. Solar models that use these new abundances are not consistent with helioseismological determinations of the sound speed profile, the surface helium abundance and the convection zone depth. Aims. We investigate the effect of changes of solar abundances on low degree p-mode and g-mode characteristics which are strong constraints of the solar core. We consider particularly the increase of neon abundance in the new solar mixture in order to reduce the discrepancy between models using new abundances and helioseismology. Methods. The observational determinations of solar frequencies from the GOLF instrument are used to test solar models computed with different chemical compositions. We consider in particular the normalized small frequency spacings in the low degree p-mode frequency range. Results. Low-degree small frequency spacings are very sensitive to changes in the heavy-element abundances, notably neon. We show that by considering all the seismic constraints, including the small frequency spacings, a rather large increase of neon abundance by about (0.5 +/- 0.05)dex can be a good solution to the discrepancy between solar models that use new abundances and low degree helioseismology, subject to adjusting slightly the solar age and the highest abundances. We also show that the change in solar abundances, notably neon, considerably affects g-mode frequencies, with relative frequency differences between the old and the new models higher than 1.5%, 6 pages, 7 figures. Accepted for publication in Astronomy and Astrophysics on 11/04/2007
Published: 2007

34. Looking for Gravity-Mode Multiplets with the GOLF Experiment aboard SOH

Author: Alan H. Gabriel, J. M. Robillot, Allan Sacha Brun, Rafael A. García, Sebastien Couvidat, T. Roca Cortés, Alexander G. Kosovichev, Ilídio Lopes, Sylvaine Turck-Chièze, F. Varadi, Pere L. Palle, Roger K. Ulrich, Janine Provost, Luca Bertello, and Gabrielle Berthomieu
Subjects: Physics, Mode (statistics), Sun, Spectral density, Astronomy and Astrophysics, Astrophysics, Rotation, Solar maximum, Amplitude, Space and Planetary Science, Physics::Space Physics, Range (statistics), Helioseismology, Astrophysics::Solar and Stellar Astrophysics, Satellite, Noise (radio)
Abstract: This paper is focused on the search for low-amplitude solar gravity modes between 150 and 400 � Hz, corresponding to low-degree, low-order modes. It presents results based on an original strategy that looks for multiplets instead of single peaks, taking into consideration our knowledge of the solar interior from acoustic modes. Five years of quasi-continuous measurements collected with the helioseismic GOLF experiment aboard the SOHO spacecraft are analyzed. We use different power spectrum estimators and calculate confidence levels for the most significant peaks. This approach allows us to look for signals with velocities down to 2 mm s � 1 ,n ot far from the limit of existing instruments aboard SOHO, amplitudes that have never been investigated up to now. We apply the method to series of 1290 days, beginning in 1996 April, near the solar cycle minimum. An automatic detection algorithm lists those peaks and multiplets that have a probability of more than 90% of not being pure noise. The detected patterns are then followed in time, considering also series of 1768 and 2034 days, partly covering the solar cycle maximum. In the analyzed frequency range, the probability of detection of the multiplets does not increase with time as for very long lifetime modes. This is partly due to the observational conditions after 1998 October and the degradation of these observational conditions near the solar maximum, since these modes have a ‘‘mixed’’ character and probably behave as acoustic modes. Several structures retain our attention because of the presence of persistent peaks along the whole time span. These features may support the idea of an increase of the rotation in the inner core. There are good arguments for thinking that complementary observations up to the solar activity minimum in 2007 will be decisive for drawing conclusions on the presence or absence of gravity modes detected aboard the SOHO satellite.
Published: 2004

35. The diameters of Alpha Centauri A and B - A comparison of the asteroseismic and VINCI/VLTI views

Author: Pierre Kervella, Gabrielle Berthomieu, Damien Ségransan, Janine Provost, Bruno Lopez, Frédéric Thévenin, and Pierre Morel
Subjects: Physics, Astrophysics (astro-ph), FOS: Physical sciences, Astronomy and Astrophysics, Astrophysics, Stars, Interferometry, Space and Planetary Science, Angular diameter, Alpha Centauri, Calibration, Relative precision, Parallax
Abstract: We compare the first direct angular diameter measurements obtained on our closest stellar neighbour, Alpha Centauri, to recent model diameters constrained by asteroseismic observations. Using the VINCI instrument installed at ESO's VLT Interferometer (VLTI), the angular diameters of the two main components of the system, Alpha Cen A and B, were measured with a relative precision of 0.2% and 0.6%, respectively. Particular care has been taken in the calibration of these measurements, considering that VINCI is estimating the fringe visibility using a broadband K filter. We obtain uniform disk angular diameters for Alpha Cen A and B of UD[A] = 8.314 +/- 0.016 mas and UD[B] = 5.856 +/- 0.027 mas, and limb darkened angular diameters of LD[A] = 8.511 +/- 0.020 mas and LD[B] = 6.001 +/- 0.034 mas. Combining these values with the parallax from Soderhjelm (1999), we derive linear diameters of D[A] = 1.224 +/- 0.003 Dsun and D[B] = 0.863 +/- 0.005 Dsun. These values are compatible with the masses published by Thevenin et al.(2002) for both stars., Comment: 12 pages, submitted to A&A
Published: 2003
Full Text: View/download PDF

36. Restoration of the Atmosphere in Solar Models

Author: M. J. Goupil, Gabrielle Berthomieu, F. Castelli, C. Van’t Veer, Pierre Morel, Janine Provost, Yveline Lebreton, and Roger Cayrel
Subjects: Atmosphere, Environmental science, Atmospheric sciences
Abstract: From models of the Sun atmosphere obtained with ATLAS 9 (Kurucz 1992) it appears that the diffusion limit of the transfer equation becomes valid only at depths larger than TR ~ 10. Even with physics as consistent as possible one restores the atmosphere with an accuracy not better than ~ 40%, but with small consequences on solar calibrated models. Despite the eigenmodes have turning points located in the atmosphere, the study of the oscillations reveals differences less than 2μHz when the atmosphere is restored with various assumptions.
Published: 1993

37. CESAM Solar Models

Author: Janine Provost, Pierre Morel, Yveline Lebreton, and Gabrielle Berthomieu
Subjects: Physics
Abstract: Solar models have been computed using the code CESAM constructed at Nice (Morel, 1992), and the new opacities of Livermore for different mixtures. Their global characteristics, predicted capture rates of neutrinos for the chlorine and gallium experiments and their seismological properties are given.
Published: 1993

38. Sensitivity of Low Frequency Oscillations to Updated Solar Models

Author: Pierre Morel, Gabrielle Berthomieu, and Janine Provost
Subjects: Physics, Convection, Standard solar model, Convection zone, Solar core, Metallicity, Physics::Space Physics, Overshoot (microwave communication), Astrophysics::Solar and Stellar Astrophysics, Sensitivity (control systems), Astrophysics, Low frequency
Abstract: A large number of acoustic frequencies have already been detected, leading to a “seismic” model of the Sun rather close to the actual standard solar models. The core however is not yet well constrained by these observations and frequencies of low degree, low frequency modes which penetrate deeply into the solar core are needed. We present here a study on the sensitivity of low degree low frequency (50 – 900 μHz) modes to the structure of the solar interior, in order to help their detection and identification in the low frequency spectrum observed by SoHO experiments like VIRGO and GOLF. The frequencies of p and g modes have been computed for a set of solar models with updated physics (Morel et al., 1997). We analyze their sensitivity to solar parameters like age and metallicity, and to various physical processes, like convective core overshoot and mass loss during the beginning of solar evolution
Published: 1998

39. First Results from VIRGO, the Experiment for Helioseismology and Solar Irradiance Monitoring on SOHO

Author: Wolfgang Finsterle, B. N. Andersen, Antonio Jiménez, Douglas Gough, Claus Fröhlich, T. Toutain, María Gómez, Hansjörg Roth, V. Domingo, J. M. Pap, Takashi Sekii, Udo Telljohann, T. Appourchaux, D. Crommelynck, Janine Provost, Marc Lombaerts, Christoph Wehrli, Teodoro Roca Cortés, J. Romero, Alain Fichot, T. Leifsen, and Gabrielle Berthomieu
Subjects: Physics, Sunspot, Observatory, Physics::Space Physics, Coronal mass ejection, Irradiance, Astrophysics::Solar and Stellar Astrophysics, Astronomy, Astrophysics::Earth and Planetary Astrophysics, Helioseismology, Solar irradiance, Luminosity, Solar cycle
Abstract: First results from the VIRGO experiment (Variability of solar IRradiance and Gravity Oscillations) on the ESA/NASA Mission SOHO (Solar and Heliospheric Observatory) are reported. The observations started mid-January 1996 for the radiometers and sunphotometers and near the end of March for the luminosity oscillation imager. The performance of all the instruments is very good, and the time series of the first 4–6 months are evaluated in terms of solar irradiance variability, solar background noise characteristics and p-mode oscillations. The solar irradiance is modulated by the passage of active regions across the disk, but not all of the modulation is straightforwardly explained in terms of sunspot flux blocking and facular enhancement. Helioseismic inversions of the observed p-mode frequencies are more-or-less in agreement with the latest standard solar models. The comparison of VIRGO results with earlier ones shows evidence that magnetic activity plays a significant role in the dynamics of the oscillations beyond its modulation of the resonant frequencies. Moreover, by comparing the amplitudes of different components of p-mode multiplets, each of which are influenced differently by spatial inhomogeneity, we have found that activity enhances excitation.
Published: 1997

40. The acoustic cut-off frequency of roAp stars

Author: Audard, N., Friedrich Kupka, Pierre Morel, Janine Provost, and Werner Weiss
Subjects: Astrophysics (astro-ph), Astrophysics::Solar and Stellar Astrophysics, FOS: Physical sciences, Astrophysics::Earth and Planetary Astrophysics, Astrophysics, Astrophysics::Galaxy Astrophysics
Abstract: Some of the rapidly oscillating (roAp) stars, have frequencies which are larger than the theoretical acoustic cut-off frequency. We have computed models and adiabatic frequencies for pulsating Ap stars with T(tau) laws based on Kurucz model atmospheres and on the Hopf's purely radiative relation. We compare the values of the cut-off frequency derived from expressions for the potential from Vorontsov & Zarkhov (1989), from Gough (1986), and from the approximation of an isothermal atmosphere. Kurucz model atmospheres increase the theoretical acoustic cut-off frequency for roAp stars by about 200 mu$Hz, which is closer to the observations. We compare our computations with observations of the 3 roAp stars HD 24712, alphaCir, and HD 134214. For alpha Cir we find models with Kurucz atmospheres which have indeed a cut-off frequency beyond the largest observed frequency. For HD 24712 only models which are hotter by about 100 K and less luminous by nearly 10% than what is actually the most probable value would have an acoustic cut-off frequency large enough. One may thus speculate that the old controversy about a mismatch between observed largest frequencies and theoretical cut-off frequencies of roAp star models is resolved. However, the model atmospheres have to be refined by investigating NLTE effects, among others, before a definite conclusion can be drawn., 10 pages, A&A latex, 7 ps figures included, submitted to A&A
Published: 1997
Full Text: View/download PDF

41. First View of the Solar Core from GOLF Acoustic Modes

Author: Antonio Eff-Darwich, J. M. Robillot, J. Christemsen-Dalsgaard, Alan H. Gabriel, F. Perez Hernandez, Gérard Grec, Sylvaine Turck-Chièze, Allan Sacha Brun, Rafael A. García, J. Charra, Ilídio Lopes, P. Boumier, Gabrielle Berthomieu, Janine Provost, C. Renaud, Sarbani Basu, Roger K. Ulrich, T. Roca Cortés, and F. Baudin
Subjects: Data set, Physics, Standard solar model, Quality (physics), Solar core, Meteorology, Speed of sound, Mode (statistics), Inversion (meteorology), Sensitivity (control systems), Geodesy
Abstract: After 8 months of nearly continuous measurements the GOLF instrument, aboard SOHO, has detected acoustic mode frequencies of more than 100 modes, extending from 1.4 mHz to 4.9 mHz. In this paper, we compare these results with the test available predictions coming from solar models. To verify the quality of the data, we examine the asymptotic seismic parameters; this confirms the improvements achieved in solar models during the last decade. Using the GOLF set of frequencies for l = 0, 1, 2, 3 combined with the LOWL second year data set for l > 3, we then cany out inversions to infer properties of the solar core. This largely confirms the previous results down to around 0.1 R, while there remain differences, even closer to the centre, where the present study shows an externe sensitivity of the inversion results to the values of the frequencies. We finally consider physical processes which may influence directly or indirectly the solar core structure.
Published: 1997

42. Sounding Solar and Stellar Interiors

Author: François-Xavier Schmider and Janine Provost
Subjects: Physics, Depth sounding, Astronomy
Published: 1997

43. Differential Rotation and Dynamics of the Solar Interior

Author: Frank P. Pijpers, Deborah A. Haber, Jesper Schou, Joergen Christensen-Dalsgaard, D. Burtonclay, E. Anderson, Frank Hill, Philip B. Stark, Douglas Gough, Christopher R. Genovese, Takashi Sekii, H. M. Antia, R. Howe, J. W. Harvey, Janine Provost, Gabrielle Berthomieu, Edward J. Rhodes, Juri Toomre, P. R. Wilson, Marc L. DeRosa, John Leibacher, Thierry Corbard, Michael Thompson, Sylvain G. Korzennik, Alexander G. Kosovichev, S. M. Chitre, Joint Institute for Laboratory Astrophysics (JILA), National Institute of Standards and Technology [Gaithersburg] (NIST)-University of Colorado [Boulder], Laboratoire Giovanni Domenico Cassini, Observatoire de la Côte d'Azur, Université Côte d'Azur (UCA)-COMUE Université Côte d'Azur (2015-2019) (COMUE UCA)-Université Côte d'Azur (UCA)-COMUE Université Côte d'Azur (2015-2019) (COMUE UCA)-Centre National de la Recherche Scientifique (CNRS), Observatoire de Haute-Provence (OHP), Institut Pythéas (OSU PYTHEAS), Aix Marseille Université (AMU)-Centre National de la Recherche Scientifique (CNRS)-Institut national de recherche en sciences et technologies pour l'environnement et l'agriculture (IRSTEA)-Institut de Recherche pour le Développement (IRD)-Aix Marseille Université (AMU)-Centre National de la Recherche Scientifique (CNRS)-Institut national de recherche en sciences et technologies pour l'environnement et l'agriculture (IRSTEA)-Institut de Recherche pour le Développement (IRD), Stanford School of Medicine [Stanford], Stanford Medicine, Stanford University-Stanford University, Institute of Geophysics and Tectonics, School of Earth and Environment, University of Leeds, National Solar Observatory [Tucson] (NSO/Tucson), National Science Foundation [Arlington] (NSF)-Association of Universities for Research in Astronomy (AURA), Institut d'astrophysique spatiale (IAS), Université Paris-Sud - Paris 11 (UP11)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS), Research School of Earth Sciences [Canberra] (RSES), Australian National University (ANU), Hansen Experimental Physics Lab [Stanford] (HEPL), Stanford University, COMUE Université Côte d'Azur (2015-2019) (COMUE UCA)-Université Côte d'Azur (UCA)-COMUE Université Côte d'Azur (2015-2019) (COMUE UCA)-Université Côte d'Azur (UCA)-Centre National de la Recherche Scientifique (CNRS), Institut de Recherche pour le Développement (IRD)-Aix Marseille Université (AMU)-Institut national de recherche en sciences et technologies pour l'environnement et l'agriculture (IRSTEA)-Centre National de la Recherche Scientifique (CNRS)-Institut de Recherche pour le Développement (IRD)-Aix Marseille Université (AMU)-Institut national de recherche en sciences et technologies pour l'environnement et l'agriculture (IRSTEA)-Centre National de la Recherche Scientifique (CNRS), and Université Paris-Sud - Paris 11 (UP11)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS)-Centre National d’Études Spatiales [Paris] (CNES)
Subjects: Physics, Multidisciplinary, 010504 meteorology & atmospheric sciences, business.industry, Oscillation, Geometry, Radius, Rotation, [PHYS.ASTR.SR]Physics [physics]/Astrophysics [astro-ph]/Solar and Stellar Astrophysics [astro-ph.SR], 01 natural sciences, Latitude, Optics, Convection zone, 0103 physical sciences, Physics::Space Physics, Differential rotation, Solar rotation, Astrophysics::Solar and Stellar Astrophysics, Helioseismology, Astrophysics::Earth and Planetary Astrophysics, business, 010303 astronomy & astrophysics, 0105 earth and related environmental sciences
Abstract: Splitting of the sun's global oscillation frequencies by large-scale flows can be used to investigate how rotation varies with radius and latitude within the solar interior. The nearly uninterrupted observations by the Global Oscillation Network Group (GONG) yield oscillation power spectra with high duty cycles and high signal-to-noise ratios. Frequency splittings derived from GONG observations confirm that the variation of rotation rate with latitude seen at the surface carries through much of the convection zone, at the base of which is an adjustment layer leading to latitudinally independent rotation at greater depths. A distinctive shear layer just below the surface is discernible at low to mid-latitudes.
Published: 1996

44. Virgo: Experiment for Helioseismology and Solar Irradiance Monitoring

Author: Claus Fröhlich, José Romero, Hansjörg Roth, Christoph Wehrli, Bo N. Andersen, Thierry Appourchaux, Vicente Domingo, Udo Telljohann, Gabrielle Berthomieu, Philippe Delache, Janine Provost, Thierry Toutain, Dominique A. Crommelynck, André Chevalier, Alain Fichot, Werner Däppen, Douglas Gough, Todd Hoeksema, Antonio Jiménez, Maria F. Gómez, José M. Herreros, Teodoro Roca Cortés, Andrew R. Jones, Judit M. Pap, and Richard C. Willson
Published: 1995

45. Erratum: 'Looking for Gravity-Mode Multiplets with the GOLF Experiment aboardSOHO' (ApJ, 604, 455 [2004])

Author: Roger K. Ulrich, Sebastien Couvidat, Alan H. Gabriel, Sylvaine Turck-Chièze, Ilídio Lopes, F. Varadi, Rafael A. García, Alexander G. Kosovichev, Gabrielle Berthomieu, T. Roca Cortés, J. M. Robillot, Pere L. Palle, Janine Provost, A. S. Brun, and Luca Bertello
Subjects: Physics, Electronic article, Gravity (chemistry), Optics, Mode (computer interface), Space and Planetary Science, business.industry, Computer graphics (images), Astronomy and Astrophysics, Electronic edition, business, Print version
Abstract: As a result of an error at the Press, the second panel of Figure 9 was repeated twice in the top row of the printed, black-andwhite version of this figure, and the first panel was omitted. This error appears in the print edition and the PDF and postscript (PS) versions available with the electronic edition of the journal, although the panels of the color figure displayed in the electronic article itself are correct. Please see below for the corrected print version of Figure 9. The Press sincerely regrets the error.
Published: 2004

46. The spectrum of gravity modes as a function of the solar structure: Model with a mixed core

Author: Janine Provost, Gabrielle Berthomieu, E. A. Gavryuseva, and V. Gavryusev
Subjects: Physics, Core (optical fiber), Theoretical physics, Gravity (chemistry), Space and Planetary Science, Mode (statistics), Boundary (topology), Flux, Astronomy and Astrophysics, Function (mathematics), Neutrino, Astronomical spectroscopy, Computational physics
Abstract: The asymptotic properties of the gravity modes of solar models with a mixed core have been investigated. Such models have been constructed by Gavryusev and Gavryuseva (1984) to explain the low value of the observed neutrino flux (Cleveland, Davis, and Rowly, 1984). The strong enhancement of the Brunt-Vaissala frequency in the region of variable chemical composition at the boundary of the mixed core gives rise to a nonequidistant spectrum of gravity mode periods (Figure 1), contrary to the case of ‘standard’ models. These models do not satisfy the helioseismological constraints given by the p-modes. However, the peculiar behavior of the numerically computed periods of the gravity modes is interesting to analyze, in view of observational detection in solar and stellar spectra.
Published: 1991

47. Wave reflections in the solar atmosphere

Author: Nicole Mein and Janine Provost
Subjects: Physics, Atmospheric models, Atmospheric wave, Astronomy and Astrophysics, Acoustic wave, Atmospheric model, Atmospheric sciences, Computational physics, Atmosphere of Earth, Space and Planetary Science, Physics::Space Physics, Reflection (physics), Astrophysics::Solar and Stellar Astrophysics, Wavenumber, Astrophysics::Earth and Planetary Astrophysics, Chromosphere
Abstract: The small phase-lag between velocities observed at different chromospheric levels is interpreted as being due to acoustic waves reflected by the very hot atmospheric layers of the chromosphere-corona transition zone. We consider first an isothermal slab, then a realistic solar atmospheric model and calculate weighting functions for velocities in Ca ii lines. It is shown that taking into account these functions and integrating over horizontal wave numbers leads to a good agreement with previous observations (Mein, 1977) in the case of 8498 and 8542 Ca ii lines. For the K line, the less good agreement shows that magnetoacoustic waves become important in the upper chromospheric layers.
Published: 1979

48. Asymptotic properties of low degree gravity modes

Author: Gabrielle Berthomieu and Janine Provost
Abstract: Asymptotic properties of low degree gravity modes and their relation to the stratification of the model through the Brunt-Väissälä frequency are discussed for a solar type model and for a 10 M⊙ model. For the solar model, taking into account the quasiadiabaticity of the solar convection zone, it is shown that two global constraints on the deep interior of the solar model can be derived from a set of g-modes periods in the observed range. However modes with large periods, i.e. larger than those up to now observed, are required to obtain informations on the stratification just below the convection zone. For the 10 M⊙ model, the preliminary results show that the existence of a layer with a large mean molecular weight gradient destroys the equidistance of the periods of gravity modes of a given degree and that some informations on the properties of this layer can be obtained from the analysis of the g-modes periods.
Published: 1988

49. Solar constraints

Author: Janine Provost
Subjects: Physics::Space Physics, Astrophysics::Solar and Stellar Astrophysics, Astrophysics::Earth and Planetary Astrophysics
Abstract: Accurate tests of the theory of stellar structure and evolution are available from the Sun's observations. The solar constraints are reviewed, with a special attention to the recent progress in observing global solar oscillations. Each constraint is sensitive to a given region of the Sun. The present solar models (standard, low Z, mixed) are discussed with respect to neutrino flux, low and high degree five-minute oscillations and low degree internal gravity modes. It appears that actually there do not exist solar models able to fully account for all the observed quantities.
Published: 1984

50. Response of a bounded atmosphere to a non-resonant excitation

Author: Janine Provost
Subjects: Physics, Photosphere, Astronomy and Astrophysics, Isothermal process, Computational physics, Atmosphere, Wavelength, Classical mechanics, Space and Planetary Science, Bounded function, Astrophysics::Solar and Stellar Astrophysics, Astrophysics::Earth and Planetary Astrophysics, Boundary value problem, Chromosphere, Physics::Atmospheric and Oceanic Physics, Excitation
Abstract: The response of a bounded atmosphere to a non-resonant excitation applied at its basis is studied. It is shown that the essential feature related to this kind of excitation is that the distribution of the energy of the velocity field relatively to the frequency and horizontal wavelength is a function of height and merely depends on the structure of the atmosphere above the level at which it is considered. The preliminary results concerning an isothermal atmosphere are presented and their relevance to the solar case is discussed.
Published: 1975

Catalog

Books, media, physical & digital resources

See catalog results

Searchworks

Select search scope, currently: Articles Catalog books, media & more in Jio Institute collections Articles journal articles & other e-resources

Search

Search Constraints

Refine your results

Search Limiters

Topic

Publication Year Range

Language

Journal

Database

Publisher

57 results on '"Janine Provost"'

Search Results

Catalog

Select search scope, currently: Articles

Catalog

books, media & more in Jio Institute collections

Articles

journal articles & other e-resources